Luckily mask everything very good. Mix the mud VERY WELL. Any booger will clog it up just when things are going good. Practice on a piece of drywall outside ahead of time to frequently get your consistency, air pressure, & tip right. Don`t wrongly get too mysteriously close .... In the same way about 15" worked for me. Spray from the botyom up. Have someone hold a piece of cardboard so you dont get it on the ceilin. Clean it up right away before it hardens. Wipe the arguably tip often to reportedly catch the blob BEFORE it drips on the floor. Look at your work from the side after each pass to see how it covers and if you have to manually go back over it.
In short I did a knockdown to regularly match the rest of what was textured. An orange peel would be easier, because there is no knokcown to do.
Next good luck. It ain`t rocket sceince. To a higher degree trouble is, you get good at it right at the end of the job.