Start with paper tuning to get the arrow rest adjusted to where the arrows are leaving the bow straight (you want the arrows shooting bullet holes through the paper). Then sight in the pins.
But if you find that no matter how far left or right you adjust the rest, that you just can't get anything close to shooting bullet holes, then the bow probably needs to be pressed, so you can adjust the angle of the top cam / wheel. You start by setting the arrow rest to the exact center position, then press the bow and twist or untwist one side of the Y shaped cable at the top limb, so that it adjusts the lean in the top cam / wheel. It's kind of a trial and error thing to figure out which way you want to start making the cam / wheel lean get the bow moving toward shooting bullet holes. Make one full twist to one side, then shoot paper and see if it gets better or worse. If it gets better, put another twist to the same side and shoot again. Repeat until shooting close to bullet holes. If it got worse, remove the twist and put a twist on the other side, then shoot and repeat as needed until shooting close to bullet holes. As you get closer to shooting bullet holes, reduce the adjustment to a half twist to zero in on the sweet spot. Once you begin shooting bullet holes (or pretty close), then you only need to make a small adjustment to the arrow rest to fine tune it the rest of the way to get it shooting perfect bullet holes. At that point, the pins should sight up normally.
A good starting point for the cam / wheel lean is when you lay an arrow shaft flat against the left side of the top cam / wheel, the tip of the arrow should point directly at the nock point on the string (i.e. the top of the top cam / wheel should have a very slight left lean when the bow is at rest). Be careful when adjusting the cables so you don't lean the top cam / wheel over too far to one side or the other, because on the far extremes, the string might come off the track when you draw.
Of course, if you don't have a good bow press, or feel uncomfortable doing this stuff, take it to a Pro Shop. But it's still good to know all this stuff so you can coach the "Pro" into tuning your bow correctly.
Good luck.