Thanks that is a start. The knob is stuck on the one under the seat. But the three point system seems to operate well. Wish it rose a bit higher for my plow. I did need the Diff lock this weekend glad to know what that is. I will now try it out. Stopped wheel spin and then use the heel level, Got it. Was trying to figure which level to it out of 4x4 I feel I don't always need it on. But maybe I am wrong.
For the knob being stuck- don’t try to force it too much or the shaft will break. Spray it with a GOOD penetrating oil like PB Blaster, Kroil, Mouse Milk…
Then try to move it in both directions since you have no idea where it is in the limit of travel. Keep spraying and trying to move it around and it should break loose eventually.
For the rear lift. Try to put the tractor end of the top link in the bottom hole on the attachment points. Then shorten the adjuster some if needed. Plows are tough since they are designed to be used below ground level. You probably need to have a transport position and then a different working position. I imagine some people would rig up a strap to hold it up higher. You might have something called draft control (if there are two levers on the right where the position control is. Position control sets the position on the three point arms. Draft control is used with plows to keep them from pulling too deep (Somehow). I think it may limit the ability to lift somehow also.