Once you have your libraries setup you can create additional sub divisions in them, for further organization of your publications:
To create a sub library, go to the Portfolio Manager and open your existing libraries:
Go to the relevant library in your overview - you can use the filter at the left to help you search - and click on the dropdown > 'Add sublibrary':
A pop-up will appear where you can choose the 'Display name':
To change the library icon, click on the tab 'Assets' and upload your image of choice.
To view all of your created sub libraries, you can click on the second icon at the left top of your library details:
As a note: Users that are assigned to the "main" library will automatically have access to all sub libraries.