How funny. I've lost so much time to accidentally hosing my system with a tweak and getting knocked back into console text mode.....and now you want to go there on purpose.
........and yet I can't remember a single way.
I prefer the happy path.
But I think your issues
may be the graphics acceleration for the Compiz desktop.
Let's see if the Marco desktop compositor is usable for you instead.
And if not, we'll go down the rabbit hole which is working out how to boot into a text mode Terminal.
Super-Key/Windows-Key/Commodore-Key + "T"
Will launch a Terminal window in the desktop even if you can't see it.
Then you can type the following, blind if necessary.
Just disregard the warning.
See if that lets you make the edits you want....if you still want to do them.
It'll probably keep booting up into marco....so if you want to change it back.
Or you can access MATE Tweak by either typing "tweak" in the Menu widget in the dock or....
From the top menu
System --> Preferences --> Look and Feel --> MATE Tweak
Then the Windows icon tab.....and the dropdown under Window manager select Compiz again.