How to adjust wipers

Hey guys! Does anyone know how I can adjust the wiper blade arms...they work fine but both need to move to the left a little more and right a little less. They "thump" after going all the way down ... like they want to go even further....and don't quite come up enough to cover the entire driver's side of the window. It's like they somehow need to be 'calibrated'. Any help would be appreciated! Thanks!