Your waterbed utilizes a vinyl liner as an extra safeguard against unlikely leakage. This liner surrounds the foam collar (and may be packaged separately). It must be installed over the foam collar, like a fitted sheet. It's important to do so after the heater is installed on the plastic netting and before filling the water mattress.
Having installed the heater and liner, unpackage the water mattress and place on top of the liner in the foam cavity. Adjust the liner and mattress in the cavity so the corner tips fit into the corners of the cavity evenly on all four sides. Remove the cap and plug from the fill spout to allow the vacuum packed mattress to expand and fill the cavity evenly.
Recheck for proper alignment of the mattress, foundation and bed frame. Be sure all cords are in the proper place and that the bed is exactly where you want it.
If you still need help, Check out our Youtube Videos for Softside and Hardside waterbed setup.
Softside Waterbed Setup on Youtube
Hardside Waterbed Setup on Youtube