1. Inspect the pool's seams. Often AG pool leaks are in the seams.

2. If you find nothing, fill the pool to 4", and see if leaks back to 2". If it does, look for leaks just below the water line.

3. If you find a likely leak, fill to 2 - 3" above the leak and dye test like this: http://youtu.be/Y90c7pYMgPc

4. Order Boxer glue and patch kits, recommended by most here, from Amazon:
Boxer Adhesives No.110 4 oz Vinyl Pool Repair Kit
Boxer 4 oz Vinyl Swimming Pool Liner Repair Kit
Boxer Vinyl Pool Repair Kit Size: 2 Oz