Operating instructions - where does the water pan...

Question

we just got a meco 5023i water smoker and put it together. even though several parts seemed to be left over - the instructions were very unclear - it seems put together ok, BUT: where does the water pan go? there's room only for one pan - presumably the charcoal pan - at the bottom, and the instructions say "put the water pan in place". and that place is? the bottom grid?we're very new to this, and quite perpelxed...thank you!