IT DEPENDS ON HOW MUCH TEXTURE YOU HAVE ON THE CEILING NOW. WHAT I FOUND EASIEST WAS
USING A SPONGE, DIPPING IT INTO THE COMPOUND AND DABBING ONTO THE CEILING.

I know of 27 different textures to put on a ceiling and walls. You are going to have to be a little more specific. If you want to know what material--joint compound is the easiest to work with.

I've used a roll-on paint which has clumps in it which provide the "cottage cheese" effect found on most sprayed on ceilings. I don't recall the product name, however I'd imagine most home centers would be able to help you find it. It comes in a bucket and is applied with a roller, and considering the size of the area you're working with I'd by a 4" roller. Good luck!