An enlarging lens. Choose an inexpensive paper at first because you will probably go through a lot of it. A piece of sheet glass or clear acrylic slightly larger than 8x10 inches. Three 8x10 plastic developing trays. Make sure the safelight is approved for the type of paper you will be using.
Many individuals are allergic to darkroom chemicals.
Interval timer to measure processing times. A watch works just fine. A light tight room, such as a dark closet or windowless bathroom. It is not critical that all three solutions be the same temperature. But if you want consistent results make sure the developer temperature stays the same during your contact printing and each printing after that.