those degree marks have everything to do with your cutting angles on your tool. but first has to be setup correctly first thing is to indicate your airbar in vertical and horizontaly put your indicator on the wheel head to indicate correctly set table and airbar to 0 and indicate in.
when that is done you need to set your finger personaly i do not care for the finger that comes with the airbars i make a solid carbide one.
to set your finger if you will notice it is off set.
put the short side towards your cup wheel set your clamp degrees to 0
and and put a small center in your airbar move you bar out to close to the finger with the cross feed at the bottom of the clamp bring the finger in to line up with the center you want the point of the finger the same hieght as the center that is in the airbar this will set the 0 degree on the airbar the when you set the clamp on any degree on the clamp ring that will be the degree you will put on your tool.
when you line finger to you cup wheel set top of finger to center of cup wheel and cup wheel should be 1 to 2 degree in front of center to protrude a sharp edge for grinding.
follow these steps and you should be able to sharpen ods on your endmills.
one more tip harig is an excellent airbar but prong to rust clean with mineral spirits and try not to touch air bar the oil in you hands will rust it keep covered with dry cloth when not in use and never move with out air attached
i hope this helps