First take stone stairs and place them in a square (doesn’t matter how big or small) . Now take stone blocks and stak them up in the middle.then take glass blocks and make them a square,make the outside blocks double. Destroy the stone block connecting the glass and ston then place water on top of the reamaining stone blocks. After destroy the stone tower thing and even out the water. Next fill the glass with lava, even it out and ur ready to go.