Here are the basic steps to Hitching Up
Back your tow vehicle as close as possible to the trailer, NEVER back up if someone is between the vehicle and the trailer
Release the coupler locking device
Lower trailer until it is seated on the hitch ball, covering it completely.
Check under the coupling to ensure the ball clamp is below the ball and not riding on top of it.
Latch the coupler to the hitch ball. Make sure it's locked in place by lifting up the trailer tongue. If it comes loose, unlatched and go back to step 3.
Make sure jack is fully raised.