Wetone is correct, un-screw and fill into pipe. Try and fill slow. I just received my piper glen and had a hard time getting the air out of all the pumps. After you fill tub to botton of head pillows, try each pump. If any pump seems not to be flowing, do not leave on, shut off and try jogging pump on/off a few times then leave off for a few hours, the air will find it's way out. If you ar ein a hurry, you can remove side panels and loosen connections on pumps to purge air. I didn't do this. I found those side panels a pain to screw back on. I left tub alone and all the air came out over the next few days. good luck
john