If you watched the previous tutorial (which is optional by the way), this one follows on by showing you how to make a Warhammer 40k style Bolter by using the polygon modelling tools in 3ds Max.
it's basic however it will teach you how to use the tools that you will be using more and more or for extruding, bevels, chamfers and all that good stuff that you have no clue about.
In 20 minutes you will learn how to make a BIG GUN thats all SHOOTY looking. That is what you want after all.
So go for it you magnificent person - learn 3D and be awesome. That is all we want!