Linhof karden color 45s question

Hi I'm new to large format photography and just got a linhof karden color 45 s everything works fine except not sure what these small black knobs at the base are for they have an arrow so I tried to turn it the way the arrow shows and the knob and part of the metal piece its attached to came off and looked as if it was glued on any help about what's those black knobs are for would be really appreciated

http://www.cameraeccentric.com/html/info/linhof_5.html
I doubt that there is much difference between the Color and Color S.

That's the shift lock. I got one of these a few years ago and that shift lock was broken as well. The previous owner had used a piece of tape to secure that movement. The tape works fine though it certainly isn't elegant. Wonderful camera, I hope you enjoy it.

Hey thanks guys appreciate the responses. Yeah I'm really psyched on the camera I've heard a lot of good things but one knob came off and the other wont turn so I'm thinking I'll return the camera and try my luck buying another one on eBay.