Well, I am still super new here too and struggle more than you'll know.
It is a good idea to go through the wiki if you click on the help button and then the question mark in Quest (For the desktop version)
I would say that if you click on your room name on the left, you will see all the tabs for the room on the right. Click on the tab called 'scripts'
Under the heading 'Before entering the room:' click on the button 'Add new script' and then enter this one liner:
ClearScreen
or let me correct this a little bit - Once you clicked on 'Add a script' you can choose 'Clear the screen' or you can click on the toggle button to view the code without clicking on 'Add a script'. It will be blank and then you just type in the code above.
That should be it.