Lay the pieces of your drum rack on the floor. You should have some parts that will function as legs and some parts that go straight across like a bar or beam. Lay them out in the setup they will be in, with the legs facing you and the beam and arm type pieces set up where they'll go when you assemble the rack.
Pick up your leg pieces and attach the rubber pads or feet sections that will allow it to be stable. You may need to lean the rack against a wall as you assemble it so it will stay upright as you build.
Pick up your beam and arm pieces and attach them either by screwing the pieces together with the turn knob screws (no screwdriver required) or sliding the pieces into the legs and across into their arm attachments. Now attach your drum pads (if it's an electronic kit) or any triggers or drum pads that you are going to use to the kit.