Does anyone know where i can find a tutorial about setting up email addresses for my domain , i have a raq3 , sorry for such a simple question but i'm new to this :(

The manual tells you how, but other than that, setting up a user on the server sets up email as well. Only set up siteadmins (chekcing the box), if you want that user to be able to control the main site.

Short help:
Set up user on a domain.
Hostname will be either the domain itself or the server name or server IP, etc.
Username will be the user you set up.
Password will be the password for the user.

If you are confused because there seems to be no way to set up *just* an email user, then just know that is how the RaQs work.