Skin Help PLEASE!

Hey everyone! I am interesting in making new skins for the game, however, I have little knowledge of how to go about it as I am just starting. So I have a couple of questions.

First, How do you deal with Island UV wrapping in photoshop? Whether is projection or target mode, I have a hard time trying to make everything look as one unit. For example, If I want to plaster a 2d image across the front of the tank, it will get cut out and some parts of the image will end up in another location of the tank, due to the many polygons the tank has. If anyone could please upload a, sort of "tutorial video" of the actual process of making a new skin, that would be really helpful, since I will be able to see and understan how you dealt with this problem. I think this would work better than any explanation over text. You don't have to talk or explain anything. Just showing the steps and process from start to finish could help me.

I also tried to download modded skins with Archive Viewer but I couldn't open the .rgt file. How can I convert .rtg files so that I can open the skins other people made in photoshop and look at how they did their skins.

Your help and time is greatly appreciated. Thanks!

I do not know much about making skins but this video may help.