There are two ways to create a collection.
Navigate to an asset that you wish to place in your new collection.
Hover over the asset, and click the Folder icon.
From the menu, click the Add New Collection icon.
In the New Collection field, enter a name for your new collection.
Click the + icon next to the field.
Your new collection is then created, with your chosen asset inside. Your new collection will appear in the Collections carousel on the MAM dashboard.
In the Collections carousel, click the + icon.
Give your collection a name. You can also choose a parent collection for this new collection if required.
Click the + icon, and your new collection will be added to the carousel.