While George shoots on a DSLR and does discuss how to shoot using a DSLR, his techniques and theories are translatable to any camera: DSLR, point-and-shoot, even the one on your phone!
Whenever you're ready! The lessons are available online any time, and your access to the class never expires.
As long as you need! Your access never expires, so you can come back again and again.
Ask your questions on the platform and you'll receive instructor feedback. Your fellow students are also likely to jump in and offer advice from their experiences.