Is it possible to use Microsoft Remote Desktop 10, to remotly view another users session, so i can talk them through an issue (Teamviewer style) instead of making the host computers screen go blank, which is what MRD is currently doing to the host machine ?
Microsoft Remote Desktop is designed for the remote user to have their own desktop working environment and as such is not designed for screen sharing like LogMeIn or Teamviewer.
If you are looking for a free screen sharing solution or one that does not count on someone else's network infrastructure you might look into using VNC. It is common on Linux machines but as it is open source also available on Windows, Mac and a bunch of OSs you have possibly not even heard of. In fact macOS screen sharing/Remote Desktop is based on VNC.
There are a lot of versions of VNC out there I linked to the first one that came up in an internet search. There are many others.