How to find movies I have transferred to an ipad

I am trying to transfer movies from my linux box to my ipad running iOS 8. I first just mounted the ipad and copied a movie to DCIM/100APPLE where it is sitting with all my other photos and movies taken from the ipad camera.

How do I find the movie I copied to play it on the ipad?

I then downloaded Documents 5 (a free app) and downloaded a movie into what Documents 5 calls "Downloads". I can try to play it from within Documents 5 but it has no sound. I have cinexplayer installed which might be able to play it properly but,

How can I get cinexplayer to find the movie that Documents 5 has downloaded?