Overall the opening is a reversal of all things performed at closing time, plus, the clean up of all associated and accumulated mess.
~ clean leaves & slop off tarp style covers using leaf rakes, brushes,
a trash pump is ideal, however water can be removed with a small pump or siphon hose.
Often the cover can be clean before its pulled off the pool, or it can be scrubbed out on the driveway or lawn.
The cover can also be treated with an anti-mildew reagent.
Fold and store cover as deemed fit. Store out of the reach of mice.
~ reassemble the equipment , tighten unions and clamps and restart the pump and filter.
~turn on the gas and test the heater when ready, follow manufacturers instructions!
Heaters are gas appliances just as a furnace is, theoretically the gas portion of the appliance should be cleaned annually by a gas technician to prevent malfunction.
~clean the pool as needed
~ a shock and a thorough water balance will be necessary
~reassemble and test lights
Scrub Deck: with mild detergent or diluted acid if necessary
Enjoy a long summer as a pool owner.