Gun Request (I'll provide the model)

[KorianHUN]

http://tf3dm.com/3d-model/wastelande-rifle-9000-poly-72623.html

This is the link to the model, it will be available for download, from 2014.02.16. or 17. / ! Year-month-day FORMAT ! /
I want to use my modelled guns i nthe game, but i daon't know how to make good textures and how to put a model into the game.
Please someone with minimal experience answer to my request.