Everyone has hit it pretty well so there's not too much to add. As you tune be sure to find a comfortable mix of "tunning" and "learning to shoot". I think sometimes folks start right off with fine tunning because "thats what the old timers do" and they forget that their inexperience has as much to do with what the arrow is doing as their set up. Id say, tune it for good flight and low noise, and then as you start to get very consistent with your groups and results, ease in to fine tunning. Just get comfortable and have fun shooting and warming up those trad bow muscle groups.
Also, as per your original question, keeping a bow square around is a good idea, but I just put a small line on an arrow at the back of the shelf once my brace is spot on, then youve got a good "brace check" device in hand always. Welcome to the gang and happy shooting!!