There's no manual, how do I select what photos I want to sell to the dealer?

First you'd have to go to the Video Equipment Store and have the photos developed (takes a few hours).
After that you'd be able to select and sell the photos to the distributor.

you can press F1 for video help ( films are different according to place where you use this option)

The part I need help at, it's just playing a video of a cat every time =[