buddy, the jacks are to stabilize. You put a little tension on them, but not enough to do all your leveling for you.
Before you unhitch, check the trailers side to side level. If it's within half a bubble, call it good. If more, lay the level blocks of your choice next to the low side tires and then pull forward. Push the blocks behind the tires and back up on them. Check the level again and if it's good, set your wheel chocks and unhitch.
Set your front to back level with the tongue jack. Once level, starting in the back, put down the stabilizer jacks, low side first, then do the fronts.
I only hook up the sewer hose when I'm ready to dump, but that's just me. Most folks hook up from day one. Leave the black tank closed until you want to dump.. There is not enough water to flow it out like at home. I like to leave the grey tank closed to fill up too, but that's optional.
The reason you want to leave the black tank until it's full is it will drain a lot better and get most of the solids out in just the drain. You may still need to fill it with water from a green hose and drain again to make sure you get the solids out. I like to finish up with dumping the grey tank, so it kinda rinses out the hose.. It's still nasty water, but not as nasty as the black tank!
Still lots to learn, but we all figured it out eventually!
Enjoy.
Mitch