If you open the top of the filter canister, there should be a plate that your filter sits on. It can be removed, gently. Under it is the pump itself. The pump cover is held on by 5 or 6 screws. Remove them. that plastic star you now see is your impeller. you can pull it out, as it is nothing but a magnet on a shaft.
Connect the intake of your pond pump the the suction outlet of your pool. Pond pump pressure outlet then goes to what would have been the suction side of your old pump, with the pressure side from the old pump going to your pool.
Does this make any sense to you? I hope I've explained it clearly enough!