It all depends on what type of ceiling want to install. What does your existing ceiling look like and why do you want to replace it? Depending on how you wish to go about this project relies strictly upon you. Obviously you are not in the home improvement business or you wouldn't be seeking this advice. What do you want to do? Your question is not very specific. If you want to hang a drop ceiling, the process is rather simple. All you need for tools are a six foot level, a nine inch magnetic torpedo level, and a pair of tin snips. After you make your measurement, (find the square footage of your existing ceiling) you will have to make a material list of things you will need to get started. Ceiling tile etc. Your local Home Improvement store employees will help you with what you will need once you give them the measurement of your ceiling. Other than that, you can either demo your existing ceiling right down to the joists, remove all screws and/or nails and install new 1/2" sheetrock, tape, three coats of compound, sand, prime and finally your finish coat of ceiling paint. Another option is to simply go over your existing ceiling with 1/4" sheetrock, which is probably the easier less expensive way to go. Of course it would be only logical to find where your ceiling joists are first before install the drywall so you will know exactly where to drive your screws for a secure bite into your existing ceiling. Good luck with whatever you decide. Hope I've been somewhat helpful! Take care and God Bless.