Map a folder on iMac to RDP session

I'm using Microsoft Remote Desktop 8.026 and need to map a folder on my iMac to the desktop of the remote computer. It used to a simple window in which this could be done in 2.1.1. Now it isn't obvious if it even is possible. If it is possible, it seems that the Remote Resources button may be the answer, but I'm stumped on what to do once I'm in there. It is asking for a URL, user name and pw. Any help is appreciated.

I realize this is primarily a forum for Apple Remote Desktop, but didn't see anything specific to Microsoft RDP.