As far as how i made it. If you knew what my pen looked like before, i just put a board on the east side bewteen the 4x4s (south wall 4x4 with the brown nest box and the middle 4x4 that holds up the net) which ends up being the wall the waterfowl sets on, then i put a 2x4 on the south wall between the 4x4s, then i went to the west wall where i had a short board screwed vertically to the existing 2x4 on the outside where it holds up the tin. I went on the outside and screwed another 2x4 threw the tin to the corner 4x4 and the new board, then i got yet another board and screwed it on the north side between the middle 4x4 (the one that holds up the net) and the vertical board i had already screwed in. By this time i had a box made and had places on 3 sides i could drape the liner over. I then took 2 large wooden posts and put them beside the tin on the south side and just under the board on the north side (that way when the liner fills it doesn't try and expand out under the board and has something to put pressure on. Once i got the liner the way i wanted it i had to take a small board piece and screw it threw the liner into the 2x4 i had placed on the west wall threw the tin (to hold the liner up). From here it was a matter of using small 2x4 pieces under the liner adjusting the width of end to which the water flows and putting more rock around it for decoration. If you have the money i would recommend getting something like cinder block or landscaping timbers to build walls on all four sides.