very new and have question?

where and how do i set up the unix machine so that back space works ?

I'm guessing thet your backspace key produces either a ^H or a ^?. One way to fix this is to type:
stty erase <backspace>

(i.e. hit your backspace key for the last charecter on the line)

You can put this in your .profile or .cshrc as appropriate to run everytime you login.

You have a couple of choices. Try reading the manpages for:

(1) stty

(2) xmodmap

stty erase <backspace_key>