Best bet would be a bike co-op where they could help you set it up correctly. Otherwise search for tutorials on RD adjustment. There are many, both text and photo and video. Review a few until you understand the basics, than follow the steps in the best one in sequence.

Two hints which might help.

1- understand that the limit screw is just what the name implies. It's a final stop to prevent the RD from going into the wheel. Adjust it by pushing the RD from the lower body (not using the shifter) and you want to loosen until it's possible to overshift (low speed), then bring it back in by degrees that you reliably can't any more, plus up to 1/4 turn as a safety margin (but no more). Then fine tune shifting using the cable adjuster for best shifting.

2- if, after adjusting to the best of your ability, it's still not OK, the hanger may not be aligned correctly. You can do a quick eyeball check, which should be accurate enough for your needs. Shift to any gear where the RD cage is fairly vertical. Place a straightedge (yardstick, or broom handle) vertical against the wheel, and stand behind and eyeball toi see if the cage and ruler are parallel. If not, then you'll want that attended to.