Make sure that your are logged in to the EDMS. Note down the document number of the
document you would like to move, e.g. Doc #980286.
Click on the node in the tree to which you would like to attach it.
Access the "Documents" tab.
Click on the "Attach" button.
Type the document ID (or search for it)
Mark the document(s) to be attached and click on the "Attached document" button.
You have now attached your document to a new node in the tree.
To remove it you do perfom the same series of operations but instead of clicking "New" under the documents tab your just access on the Item/project page, you simply click "Detach".