1. Go to Manage Devices and change the view to “Tree View”.
2. Left-click on the library and select "Modify...".
3. Left-click on the library and select "Configure...".
4. Select the "Mixed Media" tab.

5. The Mixed Media tab will have three fields:
Slot Types: Here we'll configure an identifier for the range of slots holding a specific kind of media type.
Drive Types: Here we'll configure an identifier for the type of drive on the library bay. The order will be the same one as the list on the GUI.
Drive Types/Media Type Compatibilities: Here we'll associate the slot and drives identifiers created on the previous boxes.
Using the last screenshot as an example.
On the first field, we have created two identifiers "LTO4Media" which will include slots 1 through 12, and "LTO7Media" which includes slots 13 through 24.
This means slots 1 through 12 holds an LTO4 media and slots 13 through 24 hold LTO7 media.
In the second field, we created an identifier for each drive: "LTO4" and "LTO7".
The first bay is occupied by the LTO4 drive so we identify this as "LTO4=1".
The second bay is occupied by an LTO7 drive so we identify this as "LTO7=2".
Finally, on the third field, we associate the identifiers we have created for the drives on the bays and the different kinds of media on the slots:
LTO4=LTO4Media
LTO7=LTO7Media
6. Click OK.
7. Click on Save on the bottom right.