You need to install a 1/4" underlayment ontop of your existing flooring, this so nothing telegraphs through to the new vinyl. And depeding on what brand of vinyl you install there will be specific adhesives, underlayment and adhesive trowel sizes to use per the manufacturer. Below is a link to show you lots of details about how to prepare and install a vinyl floor. Good luck
http://www.rd.com/familyhandyman/art...vinyl/cut.html