[Perfectlap]

use FX 100 over your regualr sealant (Klasse All in One, Poorboys' EX, etc.)
Let the FX dry for at least an hour.
The 425 can over anything at any time. Don't squirt the 425 onto your towel, its too thick you'll end up wasting product. Spray directly onto the car (I let it run down each panel) and use a short nap polishing towel like Sonus Der Wunder polishing towel to spread it. Follow up with a proper buffing towel (Meguiar's Gold Class or try the new HIGH QUALITY Mother's line).

There's FK products are very newbie friendly. Not much technique just use the right towels.

p.s. the pink wax they sell has the same anti static properties as 425.