How to mod?

Here is my first model of an M18 smoke grenade, using 3ds max

[url]http://s1097.photobucket.com/albums/g346/DarkMasterWorm/?action=view&current=SmokeGrenade.jpg[/URL]

For a mod can you use the same maps from the game just rename/ slightly edit them? I'm saying you don't have to do a full scale mod if you don't want to. Like just do new skins or add in different guns and you could call it a mod?

A mod I am tooling around with I don't if I can call it a mod. Just a few new weapons. And I would just edit the existing maps (if that is possible). I know many people here are against modern warfare, but I feel like many saddened BF3 fans will be here craving for a modern warfare mod. I have about 3 of the models done so far.

Red Autumn: A Red Orchestra 2: Heroes of Stalingrad mod based on modern infantry combat on the city of Stalingrad between the nations of Germany and Russia in the Fall of 2012.


German Weapons:
Assault: G36
Specialist: MP5
Support: MG4
Recon: G22
Pistol: USP 45.


Russian Weapons:
Assault: AK-107
Specialist: PP-2000
Support: PKM