Euhm deer friends, the problem is solved
Next to the door, the is a 'bookshelve' or something. Don't know my english that well
I noticed i can click on it , and voila , i can adjust the gameplay settings.
Before i started my first mission i couldn't click on that 'bookshelve' , neither on the door.
If this is a bug , or programmed to be enabled after the first mission, i dunno, but im glad it worked out well
thanks for the help tough