Cover Image and slideshow - newbie of NG questions

Hello you all
I'm a newbie of Node Gallery than excuse me of my possible stupid questions.
I'm in trouble with two issues that i don't understand how to solve:

1) When i use "cover image thumbnails" i right see only one image (it seems the first of items) but Colorbox slideshow does not show all gallery items.
2) It is possible to assign a custom Cover image for each gallery?
3) Cover Image Thumbnail View has the reference "Gallery Cover Item" but i don't find it in Node->Gallery ; where is it?
4) There is another way to have the first image (thumbnail) only in gallery page and from it runs the full gallery slideshow?

Thanks to all can help me.