First OSMC is an operatingsystem, based on debian. But to answer you main question I’ve made a little installer to get X-windows + Chromuim, running on your OSMC devivce. I also fixed a launcher for Kodi, to stop kodi and start Xwindows and restarts Kodi when you logout of Xwindows.
Next time you might wanna use the search function buildt into this forum