Depending on the era, it may also have a thermostat that is sensitive to barometric pressure changes. If so, you just need to watch the temperature more carefully than if not, and adjust.
For storing prior to setting, UVA extension had a nice writeup - basically choose clean ones, or wipe off with minimal washing if you must use ones that are not clean - poop (bacteria) is bad, but so is washing the "bloom" off. Store point-down at cool room temperature (50-65F - 10-18C) and raise one end of the carton on a 2x4, alternating ends each day until you set them.
Many extension sites have good hatching info, but that was the only one I found with info about storing before hatching.
Worked for me when we had one working hen and wanted to set a batch, so some of the eggs were over a week old, stored that way, by the time we set them to incubating. If you don't have to wait that long, don't.
Our incubator is over 25 years old, styrofoam, and air-pressure sensitive. I keep swearing I'll fix up a better temperature control for it, but haven't yet. Be sure you have a thermometer you can trust, and check it religiously before you turn. Turn 3-5x per day, stop turning about day 17 or 18 (check that timing). Wash & dry your hands before you turn, and disinfect the incubator before you start. Candling can be helpful to judge progress, but is hard even with a really good light (LED flashlights are nice) on non-white eggs. Still, it can help to eat rather than set eggs with otherwise invisible shell cracks. Temperature should be measured at the top of the eggs. Even if you managed to find an automatic turner that worked with a styrofoam incubator, you should still open the top a few times a day for ventilation (not long - manual turning provides adequate ventilation without too much time for the eggs to cool down.)
We've had two successful hatches from this relic with kids doing (and sometimes flaking on) the turning and temperature checking. Third is in progress now. The appeal of a fully automatic unit is obvious, but the expense is kinda high...unless you get the fully automatic version that's powered by chicken feed, and those have not been treated kindly by modern chicken breeding - but if you get one, use her.