...... On what surface pool should be built? 

Pools can be set up on grass, compacted dirt, or pavement that is completely flat, level and stable. A ground cloth or tarp is recommended for under the pool. The pool should not be set up on sand or muddy ground that could possibly shift. It is not recommended to be set up on wooden decks, balconies or elevated platforms. Do not drag the liner across the concrete, as abrasions will cause holes.