The consistency of the mud will change, but the thickness on the wall is whatever is required to finish the wall.
Premixed mud, cream it with a mixing wand or with your knife in the pan before using. Most of the time it is helpful to thin it down slightly, which aids in applying thin, smooth, even coats. In a full pan of mud, I'd add a tablespoon or two of clean water, that should be more than enough thinning, but you can add more or less, depending on your preferences.
Hot muds, powder mixes that cure quickly, should be mixed with as little water as possible to make the material workable. The more water you add, the longer it will take to dry. However, too little water and it will fire in your pan before you have a chance to get it on the wall. It takes practice to get the water ratio just right for your working conditions and your level of expertise.
Mud application - When using paper tape, you have to apply a thin, even layer of mud to bed the tape into. Press the tape into the mud with your knife, smoothing and removing excess mud. If you don't put down enough mud or you press too hard and take too much out from under the tape, the tape will release from the wall once it dries, resulting if failed joints and visible air bubbles under the tape. Skim about a 1/8" thick layer of mud, bed the tape and lay it off, then skim another coat of mud over the top. When dry you will top coat at least two more times, sometimes more, to finish the joint.
What products to use: Hot mud and premix joint compounds are good for taping and second coat, these products are more tacky and dry harder. Lightweight, multi-purpose, or topping compounds are used for final coat because these products are softer and sand more easily.
Shannon should have some taping vids, if he doesn't, YT is full of them. It will take some time to learn and hone the technique of applying mud, but once you do there should be little to no sanding necessary when you're done. The biggest piece of advice I can give you is to work cleanly, don't leave gobs on the wall that you have to sand off later, try to feather your edges, this prevents excessive mudding and sanding later. And finally, scrape the entire surface down with your drywall knife after it's dry and between coats to knock off any large lumps/bumps. Once the final coat is dry, run your hand across the surface with a sanding block in the other to hit any rough spots and to feather in anything that needs a little fine tuning. Mark the spots that need more mudding attention with a pencil to come back to later.
If the women don't find you handsome, they should at least find you handy.