Pre soak softens stubborn soil on your car making it easier to remove and lessens the chances of scratching in the process.
Wash Soap....pretty explanatory.
Wax is for protection. Some against scratches, but mostly against environmental contaminants and UV in some cases.
Polish removes very minor scratching with mild abrasives.
Glaze helps cover up and fill some scratches. Doesn't fix them, just hides them and is usually topped by a wax to get any sort of durability.
Compound is used for removing more stubborn defects in the paint or when you are forced to wet sand it is the first step in bringing back the gloss followed by a polish, optional glaze, and then wax.
I use Meguiars Gold Class for soap...never needed a pre soak. I use Mequiars Ultimate for compound and polish. For wax I use Duragloss 105, Collinite 845, or Meguiars ultimate. Sometimes I use Eagle One Nanowax spray wax to make them last a bit longer between applications.
