68 camaro rs manual steering

My 68 camaro has the oringnal manual steering.On the top of the steering box has a removal bolt to put in lube and also has a adjustment for the steering box which you adjust with a screw diver. My question is how do I adjust it and what does the adjust do for the steering.

It can remove slop in the steering gear, but make sure that if slop exists that the problem is not elsewhere before adjusting the box.
Rule of thumb is to loosen the lock nut, tighten the screw until it’s just snug, and then back if off about an 1/8 of a turn. If you get it too tight you may find that the car will not want to straighten itself out after making a turn.

Thanks for the info. Do you know what kind of lube goes in the steering box and do I fill it up full?