Firstly, you'll want to check that your cd recorder is correctly configured. You may do this by entering the command "cdrecord -scanbus" while logged in as root (or having used "su").
Assuming the above output shows that your burner is recognised, you will now want to proceed to create an iso filesystem to burn to the cd. You can do this using the mkisofs program - don't forget to read the manpage: "man mkisofs". A typical command line might be something like:
mkisofs -J -o /tmp/mycd.iso /home/myuser/
Having successfully created an iso, you can write this to a recordable disc (preferably CDRW until you're sure everything works) using cdrecord. A typical cdrecord command line might read something like
cdrecord dev=0,0,0 speed=12 blank=fast -data /tmp/mycd.iso
The blank=fast part is only applicable to reburning a cdrw - be sure to remove it if you're working with CD-Rs.
Having said all that, there are several functional GUI solutions for burning cds under linux. Although I don't use any myself, perhaps someone else can provide a recommendation?