The documents are identified by a code, a type (that must be in the table of document types) and a description.
To add a document, you must enter a code, select the type and give it a title. Then click the Browse button and select the desired file. When loaded, save with OK. It appears in the list on the left.
The Usage button shows which records (items, routing, …) are attached to that document.
The Test button lets you preview a document.