It's virtually impossible to "!@#$ up" closing a modern pool. Your pump has a fitting on it that's capped. You hook up an air compressor to that fitting and blow air through the system. Each line blows individually. When one "blows", you cap it and move on to the next.
Toss in the right chemicals and cover it up and you're done. All you need is a "gizmo" (plastic thing that screws into the skimmer), the right fitting for your pump, and a compressor.
Opening is even easier. You "prime" the pump by filling it with water and take off all the caps and the "gizmo" you screwed into the lines. Toss in some shock, algecide, and "Pool Perfect" and you're off.