Position King Pin plate 1" lower than hitch head plate so that when you back into king pin it rides up onto hitch head plate......that will prevent high hitching.
Hitch handle should pull out fairly easily completely opening jaw(s) and should snap closed if you let go of handle.......spring pulls jaw(s) closed.
Check manually the operation of handle/jaw(s) and clean/lube all pivot points.
Do NOT attempt to move/tow 5vr until jaw(s) and handle fully close.
After hitching..visually check/confirmed do a 'pull test'
Raise front landing gear 1" off ground
Then place truck in "D"......engage trailer brakes via manual lever--full on
Then slowly pull forward placing force on hitch/jaw/king pin. Properly hitched, king pin will not pull out of hitch jaw(s)
