Prerequisite: You’ve installed Ubuntu 18.04 with Cinnamon (sudo apt install cinnamon-desktop-environment) and you want to remote into it from a windows computer or from another Linux box with remmina or vinagre using rdp (remote desktop protocol). No problem!
Server setup on your Linux box
Step 1: ctrl+alt+t to open a terminal
Step 2: type sudo apt install xrdp vnc4server && echo “cinnamon-session” > ~/.xsession && sudo service xrdp restart && inxi -i
Done, the server is set up and you should note your local ip-v4 address (e.g. 192.168.1.100)
Now to connect from a Windows computer
Step 1: winkey +r, mstsc <enter>
Step 2: type the IP of your linux box