bulb users can create multiple collection levels. It allows you to organize your pages in a structure similar to the folders on your computer.
1. On your profile, go to the collection you would like to organize.
Notice in the upper left corner of your screen there is a breadcrumb trail showing that you are inside of a collection - see image below for reference. You can always use this breadcrumb to navigate between your profile and the collections you are in.
2. Create a new sub-collection by clicking CREATE COLLECTION
3. Create your new collection.
4. Drag and drop to re-organize your content.