[lug] Ummmmm....not a linux user yet, but I'd like to try it out....

Hello People,
First time on here, so apologies if I'm breaking any etiquette rules.
I've got an old machine sitting here ( AMD K6 ) and I've been intrigued
by the thought of trying to run an operating system other than Windows
on it.
I've tried playing around with some of the freebie distros that
occasionally get attached to the front of magazines, but I think I'm
missing something obvious.......( that or I'm stupid )......because I
never seem to be able to get them to work.
Would someone be kind enough to advise me as to the most simple form of
getting into this linux business?
Things I haven't been able to do...connect to the net, find any
hardware.....you name it....I can't do it.
I'm sure that once someone points me in the right direction, I can
start to enjoy this.
Thanks in advance,
Unidentifiedbones