The “browse” pane works in much the same way as the Browse Files page does. The main differences are that:
- you can add a clause directly to your document
- you cannot create, edit or move files when in the Assemble Document mode (you can create new folders, however)
Having browsed to the clause you want to add, clicking it will show a preview of its title and body text in the bottom pane. You can then add it by clicking one of the plus signs as explained here.