Latex gloves from Harbor Freight, crappy old clothes, and just get DIRTY!
Plan on it being a very sloppy messy process. We dunked out burlap in the bucket, rolled it around, then just slapped it in place. After we were done positioning, we used up the rest of the mud by hand and scooped it onto the areas that needed more.
You could use drywall tools if you're trying to be more precise and accurate, as well.