In this section we assume that you are using CVS only on the client side. That means, someone (probably the administrator of the CVS repository) gave you an account on the server machine, and it's your job to checkout modules from the repository and work with them.
CVS supports several methods of accessing the repository, which can be categorized as follows:
Local - The repository name is something like /home/cvs/ and is simply stored in a directory which is accessible from your computer. It may physically be on a disk which is mounted via NFS, but this an irrelevant detail. If you often use a certain local repository, you will want to tell Cervisia about it: First, open the Repositories dialog by chosing Repository->Repositories.... Now press the Add... button, enter the name of the repository and confirm by pressing OK. In the future, whenever you use the Checkout dialog, Cervisia will present you repositories you have inserted here in a combo box.
rsh - The repository name is something like :ext:bernd@cvs.cervisia.sourceforge.net:/cvsroot/cervisia. This method requires that you have a user account on the server machine (cvs.sourceforge.net in this case) and uses a remote shell for communication. By default, CVS uses rsh for this purpose. However, rsh is known to be unsecure for a long time and is meanwhile replaced by ssh on many sites. If you are forced to use ssh, you have to set the environment variable $CVS_RSH accordingly when using the cvs client. Cervisia supports this in an easy way: Open the Repositories dialog and press the Add... button. Now enter the name of the repository in the first line and the remote shell (e. g. ssh) in the second line. If you now confirm with the OK button, Cervisia memorizes these settings.
Note that Cervisia can not answer possible password requests from the server machine. You must make sure that a remote login works without requiring you to enter the password. With plain vanilla rsh, this can be achieved e. g. by creating a $HOME/.rhosts file with a list of trusted hosts (see the rsh manpage). With ssh, it can be achieved by copying your public key $HOME/.ssh/identity.pub to the server. In this case, the key must not be encrypted with a passphrase (see the ssh manpage and the CVS/SSH FAQ). If you are unsure about these issues, ask your system administrator.
pserver - The repository name looks like :pserver:gehrmab@cvs.kde.org:/home/kde. This method accesses the server via a special protocol with a relatively weak authentification (pserver stands for password authentification). Before you can use such a server, you have to login. As this isn't directly supported by Cervisia, enter on the command line cvs -d :pserver:joe@cvs.kde.org:/home/kde login (of course, with your repository substituted). CVS will prompt you for your password and check with the server. If the password is ok, the repository name, together with the (slightly scrambled) password, will be appended to the file $HOME/.cvspass. Whenever CVS accesses the repository, it will silently send the password to the server, so you do not have to take care of that once you have logged in. As everybody who knows your password can work with the repository in your name (and even do major damage to it), you should keep the $HOME/.cvspass secret and non-readable for others.