You can view all the documents that you own in Deltek Collaboration (the documents that you have uploaded to Deltek Collaboration from the view. Click Documents, then My Documents in the list of view options at the top of the Documents tab (to the right of your Home page Favorites). This will provide you with a view of all your documents.
To see the storage space used by each of your documents, click Sort on the right side of the page, then By size from the list of options that appears. The documents will be sorted in order of biggest to smallest.