Connecting a Top-level SharePoint Online Site Collection to a New Microsoft 365 Group
Microsoft offers a PowerShell cmdlet that enables you to connect a top-level SharePoint Online site collection to a new Microsoft 365 group. Refer to the Microsoft article Set-SPOSiteOffice365Group (Microsoft.Online.SharePoint.PowerShell) | Microsoft Docs for details.
You can also create group connections in bulk. Refer to the Microsoft article Connect to a Microsoft 365 group | Microsoft Docs for details.
Configuring Hub Sites
Hub sites in SharePoint Online provide a way to connect modern team sites and communication sites so that they share the following experiences without the constraints of a site/subsite relationship:
·Common navigation
·News roll up
·Search within a hub
You can register/unregister a hub, associate sites with the hub and change hub associations, and edit hub site settings either from the Content Matrix Console or using PowerShell.
Note: You can also register and associate hub sites as part of a migration to SharePoint Online if you choose to promote first level sites to site collections.
Requirements and Restrictions
·A tenant-level connection is required to perform hub site actions.
·You cannot perform hub site actions on a site that uses a read-only connection.
·Hub site actions are supported for modern team site and communication site templates only.
·Hub site actions can only be performed on one site at a time.
Configuring Hub Sites from the Content Matrix Console
From the Content Matrix Console right-click menu, you can:
·register/unregister a modern team or communication site as a hub site
·edit hub site settings
·associate a site with a hub site
·change hub site associations
To register a site as a hub site:
1.Select the modern team or communication site that you want to register as a hub site.
2.Right-click and choose Register as a Hub Site.
3.Complete the Register as a Hub Site Dialog with the following information:
a)If different than the default (the Title of the site), enter a Hub Name.
b)For Authorized People, enter either the Display Name or email address of the user(s) or security group(s) authorized to you want to allow to associate sites with the hub. You can enter multiple users/groups as a comma-separated list.
NOTE: If you leave this field blank, all users will be able to associate their sites with the hub.
4.Click [OK].
When a modern team or communication site is registered as a hub site, the icon to the left of the site is changed to 
To edit hub site settings:
1.Select the hub site for which you want to edit settings.
2.Right-click and choose Edit Hub Site Settings.
3.Update the Hub Name and/or Authorized People as appropriate.
4.Click [OK].
To associate a site with a hub site:
1.Select the modern team or communication site site that you want to associate with a hub site.
2.Right-click and choose Associate with a Hub.
3.From the Edit Hub Association dialog, Select a hub from the drop-down.
4.Click [OK].
When a site is associate with a hub, the icon to the left of the site is changed to 
To change a hub site association:
1.Select the site whose hub association you want to change.
2.Right-click and choose Change Hub Association.
3.From the Edit Hub Association dialog, Select a hub from the drop-down.
NOTE: If you want to remove a hub association completely, select None from the drop-down. The site theme and shared navigation of the last associated hub will be retained.
4.Click [OK].
To unregister a hub site:
1.Select the hub site you want to unregister.
2.Right-click and choose Unregister as a Hub Site.
3.Click [OK].
All sites associated with the hub site will be disassociated. However, these sites will retain the site theme and shared navigation previously inherited from the hub.
Configuring Hub Sites Using PowerShell
Using PowerShell, you can:
·register/unregister a modern team or communication site as a hub site
·edit hub site settings
·associate a site with a hub site
·change hub site associations
To access the PowerShell cmdlets for configuring hub sites:
Open a PowerShell or PowerShell ISE session and add the PowerShell snap-ins for the application framework.
The following cmdlets for configuring hubs are now available:
To connect to the SharePoint Online tenant:
Use the New-MLSharePoint Connection cmdlet or connect via the Content Matrix Console.
To display a list of sites in the tenant that are already registered as hub sites:
Run the Get-MLHubsites cmdlet and specify either the TenantConnectionID or TenantUrl.
To register a site as a hub site:
1.Select (from the PowerShell ISE Command Window) or enter Register-MLHubSite.
2.Provide the following information:
a)For HubName, enter the name that you want to assign to the hub.
b)Enter the SiteUrl of the modern teams or communication site that you want to register as a hub site.
c)For AuthorizedPeople, enter either the Display Name or email address of the user(s) or security group(s) authorized to you want to allow to associate sites with the hub. You can enter multiple users/groups as a comma-separated list.
NOTE: If you leave this field blank, all users will be able to associate their sites with the hub.
3.Enter either the TenantConnectionID or TenantUrl.
4.Run the cmdlet.
Example Scripts:
Register-MLHubSite -TenantConnectionId 555cff48-babd-000b-b000-12132f929d35 -SiteUrl "https://metalogixsoftware.sharepoint.com/sites/IB_Demo_STS3Source_RegisterAsHubSite" -HubName "Communication Hub" -AuthorizedPeople "devadminuser2@metalogixsoftware.onmicrosoft.com, Dev Admin User 1"
Register-MLHubSite -TenantUrl "https://metalogixsoftware-admin.sharepoint.com" -SiteUrl "https://metalogixsoftware.sharepoint.com/sites/IB_Demo_STS3Source_RegisterAsHubSite" -HubName "A" -AuthorizedPeople "devadminuser2@metalogixsoftware.onmicrosoft.com, Dev Admin User 1"
When a site is registered as a hub, the icon to the left of the site in the Content Matrix Console is changed to
1.Select (from the PowerShell ISE Command Window) or enter Edit-MLHubSiteSetting.
2.Enter the SiteUrl of the hub site that you want to edit and either the TenantConnectionID or TenantUrl.
3.Enter the HubName and AuthorizedPeople with the appropriate values.
IMPORTANT: You will need to re-enter all AuthorizedPeople, even those that have not changed. If you leave this parameter blank, all users will be able to associate their sites with the hub.
4.Click [OK].
Example Scripts:
Edit-MLHubSiteSettings -TenantConnectionId 555cff48-babd-000b-b000-12132f929d35 -SiteUrl "https://metalogixsoftware.sharepoint.com/sites/IB_Demo_STS3Source_RegisterAsHubSite" -HubName "HR Hub" -AuthorizedPeople "devadminuser3@metalogixsotware.onmicrosoft.com"
To associate a site with a hub site:
1.Select (from the PowerShell ISE Command Window) or enter Join-MLHubSite.
2.Enter the HubSiteUrl of the hub site with which you want to associate the site.
3.Enter the SiteUrl of the modern team or communication site you want to associate.
4.Enter either the TenantConnectionID or TenantUrl.
5.Run the cmdlet.
Example Script:
Join-MLHubSite HubSiteUrl https://metalogixsoftware.sharepoint.com/sites/vlad_hubSite -TenantConnectionId 555cff48-babd-484b-b381-12132f929d35 -SiteUrl "https://metalogixsoftware.sharepoint.com/sites/IB_Demo_STS3Source_RegisterAsHubSite"
When a site is associated with a hub, the icon to the left of the site in the Content Matrix Console is changed to
To change a hub association:
1.Select (from the PowerShell ISE Command Window) or enter Join-MLHubSite.
2.Enter parameters as you would if you were associating a site with a hub site, using the new HubSiteUrl.
NOTE: If you want to remove a hub association completely, enter a value of None for the HubSiteUrl. When the association is removed, the site theme and shared navigation of the last associated hub will be retained.
3.Run the cmdlet.
Example Script (to remove an association):
Join-MLHubSite HubSiteUrl none -SiteUrl "https://metalogixsoftware.sharepoint.com/sites/IB_Demo_STS3Source_RegisterAsHubSite" -TenantUrl "https://metalogixsoftware-admin.sharepoint.com"
1.Select (from the PowerShell ISE Command Window) or enter Unregister-MLHubSite.
2.Enter the SiteUrl of the hub site you want to unregister.
3.Enter either the TenantConnectionID or TenantUrl.
4.Run the cmdlet.
All sites associated with the hub site will be disassociated. However, these sites will retain the site theme and shared navigation previously inherited from the hub.
Example Script:
Unregister-MLHubSite -TenantConnectionId 555cff48-babd-484b-b381-12132f929d35 -SiteUrl "https://metalogixsoftware.sharepoint.com/sites/IB_Demo_STS3Source_RegisterAsHubSite"