How? I made a left turn at Albuquerque...
Seriously though, I joined through a direct invitation from Tom. That was way back when the site was just started and I joined under a different 'nom de plume" (Spitfire14e) than I have now. I was member number 2, right after Tom. After a succession of new computers (and lost/forgotten sign-in / passwords) I re-joined under my current moniker.