Onground assembly was easy, placing unit in the pool was a challenge: The retainer that keeps the sand in the fence needed additional screws to secure it; the fence fit loosely into holes provided and we needed extra rags to keep it in place when under water. In terms of design, it's great for kids, but does not provide much flow-through for pool water, so algae underneath can become a problem if not cleaned regularly. In light of this, our first season with the unit has been a delight!