Operation is going to depend on what control panel you have. I have a manual system that I installed back in 2013. Single pump with four jacks and my procedures are for such. Also your system could have various interlocks such as engine running and parking brake set before it will operate.
Press the power on button then the extend button. Both have red lights to the right of the button to confirm the mode. I then usually start with extending forward jacks until both jacks touch the ground. You need to press and hold the button (front, rear, left, right) for movement. Repeat with the rear jacks. Once all jacks are extended to ground contact then I'll raise which ever end of the coach is low starting front or rear then work left and right last. You can only effect jacks in pairs not individually. To retract first power on, then retract button then pick either front or rear. I normally start with the rear then front. You can retract left or right but you can really get the coach leaning with one side extended and the other retracted.
I use one of
THESE when leveling.
I didn't install the switches on the jacks to light the retract light but you can hear the sound of the pump change when a pair is fully retracted (or extended). Always do a visual check to confirm full retract as part of my final departure walk around checks. There is also a toggle switch on the pump unit that will retract all at the same time if there is a problem with the system.
Always keep at least one rear wheel on the ground. Lift them both and you lose the parking brake to hold the coach in place. If the coach shifts or slides while on the jacks nothing good is going to happen. Jacks are very strong lifting but lateral movement not so much. Bend a jack (rare but can happen) and it wont retract and you'll have to remove the jack before you can move the coach. Not difficult if you have a 12 ton bottle jack and jack stands to hold the coach while you're working under it. Lifting the front wheels off the ground without blocking under the tires is a matter of personal preference. Lots of discussion topics you can search for discussing such.
Left and right extension or retracting moves the coach pretty quickly as compared to front and back due to the angles involved. If you need to change left and right use short bursts. You can get into a loop of raising and lowering chasing a level. If so just start over by retracting all to ground contact. I found once I start retracting to chase a level the end result is usually too much jack extended so I try and only extend the jacks while leveling. I have ended up with one jack no longer touching the ground, particularly after a having to retract left or right to level. Just extend a pair (front/back) that will effect the high jack. Fluid pressure will follow the path of least resistance which will be the high jack so you should still have a reasonable level once the jack regains ground contact. Your objective is level with as little jack extension as possible. Doesn't need to be perfectly level. If you're comfortable then so is the fridge. Chasing the bubble usually ends up with the too much jack extended.
I like the system particularly the power retract rather than spring retract. I've got about three times the lifting capability of the jacks than what the coach weights. Each jack is rated at 12,000 pounds and my normal coach weight is only about 16,000 pounds.
2006 Hurricane 31D built on a 2006 Ford F53