Contact printing with paper negatives is quite easy. You don't have to use the "wet" method unless you like the mess or can't get your hands on either a contract printing frame or some 1/4" plate glass.
Easiest is just lay down the receptor sheet on the enlarger baseboard, face up. Then put down the paper negative, face down. Then put down the glass to hold flat. With a level baseboard you should get sufficient contact to make a good print.
A split back contact frame is nice to have because if you move on to some of the UV sensitive contact printing methods, you quite often need to peek inside and check progress by viewing the positive. The split back lets you do this without loosing registration.
Your other choice, a non-APUG discussable one is to simply scan the paper negative and invert/mirror in your favorite software package.