create a weapon

[Bukz]

1. Get a 3D modeling program.
   
2. Get a graphics/image editing program.
   
3. *Optional: Get a UV mapping software to make skinning/unwrapping your models easier.
   

http://google.com

Many tutorials for these different softwares exist on sites like youtube. You'll need hours of time to watch those and practice what you learn from them. Don't start off too complex, or you'll only feel discouraged much quicker than usual.

Hf, gl, HTH. :)