Fill the hoses with water and turn the valves off/closed. Fill the filter completely with water and attach the lid...some water should pour out of the filter while you're doing this. Shake or gently tap the filter to move any trapped air towards the top of the filter. Attach the hoses, open the valves, shake the filter again and plug in the filter. Pump the priming plunger to get the siphon started. The filter should start pumping water in and pumping water and air out...if not, turning the entire filter upside down for a minute to get the flow going, helps. Once the flow gets going, the filter will continue to blow out any trapped air...just keep shaking and tapping the filter to help clear all the air out and to get maximum water flow.