You need to learn Linux basics first, such as how to use a command line shell, how the file system works, and how to get help for particular commands, etc.
Id suggest starting with Ubuntu, its much easier for a novice Linux user and there is lots of online help and guides written specifically for Ubuntu.
BackTrack is a Pen Testing distro, and requires at least basic Linux knowledge to use properly. As a guide, if you cant get a network interface setup on your own (after searching Google and the forums) you probably aren't ready for BackTrack.
You'll also find that people on the forum here are much less likely to want to spoonfeed answers, and you will get flamed eventually if you kep asking basic questions. The Ubuntu forums are much more tolerant of this.