How-to: User-controlled slideshow

A good friend of mine has used Next Gen to create the perfect gallery. This is exactly what I’ve been looking for on the internet for more than a year.

I’m trying to create a gallery like his, with previous & next buttons. Mainly, where the user has control of looking at the photos.

But I can’t seem to figure out how exactly it’s done. Everything I seem to come across isn’t quite like his.

Does anyone have ideas?

Thanks!