Marc,
Like Karl said, your coach has been converted to a manual system because there are no parts available to repair the automatic system. So the original manual would be of little to no use for you.
The proper leveling procedure would be to extend the slides, dump air, extend the jacks in pairs to level the coach side to side first, and then extend the jacks in pairs to level the coach front to rear. After the coach is level, extend the unused jack until it touches before turning off the system. When departing, air up, retract all jacks, and then retract the slides.
The reason that you use jacks in pairs is to prevent twisting the coach. So if you use jacks individually to level the coach, be very careful not to twist the coach because if you cause a twist in the coach, it will break the windshield.
Gerald