In Zdoo, you have to create libraries to manage your documents. 

1. Create a document library

Click Create Library and a window will pop out for you to enter the information about the library you are going to create.

If you choose Project as the type, the Project drop-down will be displayed for you to choose a linked project.

2. Drag and drop

Drag a document in a library and you can drop it to rearrage the sequence.