Put the two metal side rails on the floor with the headboard attachments facing where the head of your bed will be.
Attach the three metal crossbars at the head, center and foot of the bed with the supplied nuts, bolts and washers. These crossbars are required to support the weight of the waterbed.
Put the feet into the legs of each of the crossbars. Each crossbar has three legs--one on each side rail and one in the middle.
Put your mattress foundation in the frame. If you have a king size bed, your foundation will be two smaller pieces.
Put the mattress cover on the foundations, unzip it and fold the cover over the sides of the foundation.
Unfold the two bolster pieces. Place the one with the two shorter pieces on the foundation first, with one bolster at the head and one at the foot of the bed. Place the side bolster pieces on the sides of the bed. You now have a cavity for the waterbed mattress between the bolsters.
Place the waterbed heater on the fabric pieces that connect your bolsters and run the heater wires out of the holes that are cut into the foam and the cover of the mattress.
Insert the vinyl waterbed liner in between the bolsters and fold the edges over the top of the bolster. Fold the edges of your mattress cover back up to encompass the bolsters and liner.
Insert your mattress into the cavity between the bolsters.
Connect the faucet connector--which is included in the waterbed fill kit--to the closest faucet without an aerator. The aerator is the small piece that screws onto a faucet to control the water stream.
Connect one end of a hose to the faucet connector and the other end to the waterbed hose connector -- a long valve, which is also included in the waterbed fill kit
Remove the cap plug insert from the mattress and pull out the bed's fill valve that sits below them. Insert the hose connector into the fill valve and turn the faucet on. Fill your mattress with lukewarm water until your mattress almost reaches the top of the bolsters.
Remove the hose, replace the plug and cap and push the valve back into the mattress. Zip the mattress cover and turn your waterbed heater on.