Step 1. Cut liner.

Adding the Liner

1. Cut the pond liner to a manageable size. A 66-inch square gives you a 1-1/2-inch allowance on all sides. Put the liner into the box and roughly center it.

2. You can divide the surplus into equal pleats on each side, or pleat all of it to one side. Then drive a few staples through the liner near the top of each side. Use heavy scissors or a utility knife to trim the liner flush with the top of the sides.

Step 2. Secure liner.

3. Position the pump inside the box, and route its cord through the notch. Cut the 2x4 cap strips to sizes shown in illustration, and screw them into place. Double-check the completed box's location (full sun is best) and level before filling it with water. You won't be able to move the box without draining it; the water alone weighs almost 600 pounds.

Step 3. Add the pump.

4. Fill the pond with water from a garden hose. (Wait 24 hours before adding any fish.) Now plug in your fountain and put your feet up.