how do I perform a file transfer using remote desktop on windows 10?
When you are configuring your remote desktop connection, there is an option that is labelled 'local resources' from there you can pass through local drives to the target machine.
You shouldn't have needed to install remote desktop from the store since the client is included by default. In the search box on the taskbar, type remote desktop and it will appear in the results, open it and click the show options button. You will then see local resources.
This is the same as every previous version of windows in the past 14 years I believe. Unless you have downloaded another type of rdp client.
Since the question was how to transfer using the windows 10 app vs the desktop program:
To transfer files I use the \192.168.1.2\c$ method (where the IP address is for the other machine). It is fast and reliable. I have a folder with c-drive shortcuts to all of the machines I remote to. I prefer the Windows Store RDC client for Windows10 clients.