Here are some video tutorials that explain how to add/edit/manage NextGen galleries in your website:
1. Adding Images and Managing Galleries:
https://www.youtube.com/watch?v=8ZWtks0hW3c
2. NextGen Gallery - Create Galleries & Albums:
https://www.youtube.com/watch?v=PW9zVyagPi0
3. NextGen Overview Gallery & Album:
https://www.youtube.com/watch?v=o0GaFYu49CU
4. NextGen Gallery Slideshow & Thumbnail Tutorial:
https://www.youtube.com/watch?v=n3t32k5Sd4o
5. How to Insert a Photo Gallery into a WordPress Post/Page:
https://www.youtube.com/watch?v=8O0swHbEdVU
