Newbie Question: PPP

["R.Feenstra" <R.Feenstra@cdfire.demon.nl>]

I'm running Debian 2.1 Slink since one week and now I'm trying to get
my ISDN card to work.Installed isdnutils.
The first problem i run into is when i give the command pon I get the
response :
/usr/bin/pppd:This system lacks kernel support for PPP.
This could be because the PPPkernelmodule is not loaded,or because the
kernel is not configured for PPP.

My question : How can I configure the kernel for PPP and load the module ?
Please step by step advice because I'm a real newbie in this.
I'll apreciate any help.

Rene