If it's a reputable bow shop then THEY can't tune a bow for you. What They can do is set the rest for centershot, nocking point for approximate height. Tweak the draw length and weight for YOU.

Then YOU shoot the bow and tune accordingly for the best arrow flight. This may be paper tuning or bare shaft, walk-back tuning or whatever method is used.

The reason THEY can't tune the bow for you is that each shooter may grip or otherwise shoot the bow differently and it must be tuned for that particular individual. They may help with the tuning process in that they can be there and observe what is happening and make the necessary adjustments. More importantly they can teach you how to do it in the future so you don't have to rely on them.