The front forks each have a Schrader valve on them to release excess air that may be in them...you don't ever add air to them. With the bike on a stand and the front suspension fully extended, let any excess air out of the forks.
The Schrader valve on the rear shock should not be touched! It is used (with special equipment) to charge the rear shock with nitrogen ONLY.
I'll move this to the suspension forum and suggest that you ask individual, specific questions. You typically get better answers that way. Most people don't have the time to answer broad, general questions, but will take the time to answer specific ones.