The links Jax provided above are good ones - in the "Herding German Shepherds" group on Facebook you'll see dogs with different pedigrees doing different things. If you live near New York state, you may be able to get involved with the only (I think?) active HGH opportunity in this country.
To be brutally honest, there aren't very many German Shepherds actively involved working sheep. A few here, a few there. Trust me, I'm always looking... I've been involved for about six years, and have only met a handful. Hundreds of GSD owners get an instinct test and never go any further.
If you're thinking about it for the future, I strongly recommend attending as many all-breed trials as you can. USBCHA are almost exclusively border collies, it's a shock to see any other breed entered - though there have been a few, I've been told. Personally I've never seen one, and I go to at least one or two USBCHA trials each year as a spectator. There's AHBA, AKC, and ASCA (gives preference to Aussies but other herding breeds are welcome).
The foundation/raising of puppies is very much the same, regardless of breed, and you'll be able to pick up tips and opinions on how to raise your dog to set yourself up for success. It's a steep learning curve, and you also need to learn about different kinds of sheep (there are MANY variables), different kinds of fencing, and what a livestock guardian is or is not. Most people I know use alpacas or donkeys, a few use guardian dog breeds, I don't know of anyone who has ever used their GSD to guard sheep 24/7. Immerse yourself.... you can spend an absolute lifetime learning about stockdogs, and still have more to learn. It's very humbling.