PC (so far this is working only in wayland)
First, open a Terminal window and run:
gsettings set org.gnome.desktop.remote-desktop.rdp screen-share-mode extend. This step is needed to enable extendable virtual monitors over RDP. This feature is, at present, a hidden one because this stuff isn’t polished enough for the masses to make use of yet — so be aware!Copy your IP address: go to Settings > Network, click the cog icon next to your active network, find your IP in the ‘details’ pane.
Next, open the Settings app, navigate to the Sharing panel, and turn on Sharing, and turn on (once it appears) the ‘Remote Desktop’ option. You will want to set up a username and password too, to allow you to connect from a different device.
Tablet
Use an RDP client on your tablet/phone (you can use Remote Desktop Mobile) — to connect to your computer from your tablet using your local IP (plus the right login credentials, if set previously).
In Remote Desktop Mobile app just tap the “+” icon, enter your PCs IP address, and the user credentials you created previously. Make sure you hit the ‘save’ button before backing out or you’ll have to do it again.