When you turn a ZTR you have to use the 3 point type turn or they will tear the lawn up.
I use one of these to set my decks.
https://www.amazon.com/Oregon-42-095...20289990&psc=1
In your shop or on level concrete, set your deck at the height you mow at. Check your tire pressure and make sure they are all correct. Turn your blades so they are parallel with the frame rail. Then adjust the deck so that the blades are about 1/4" lower in the front. Then turn them perpendicular to the frame rails and check the height on the outer blades and make sure they are the same height. Once this is done then your deck should be set up properly.