Hello, and welcome to the forums!
The procedure of getting the models in-game is a bit confusing at the first looks, but it's not hard after you get the basics of it.
Put
really short, it consists of:
Making your 3d mesh > mapping your mesh > creating the texpage > converting the mapped model to PIE format, adjusting the scale properly and separating the turret and barrel models, before doing that, preferrably > assemblying a folder structure coherent with the game's structure > editing the .wrf files for them to load your stuff > storing and testing your .wz pack > watching for stderr.txt file > repeating the last 4 steps until it works.
The first 3 pages should be already be of your knowledge, here's not the *right* place for learning the technical aspect of them anyway

the texpages should be .png format.
To convert your models to .PIE format, you'd be better off using the "3ds2pie" converter tool, search for it on the forums, it's somewhat easy to find. It's a proccess of (sometimes boring) trial-and-error to adjust the scale of the models.
To see what's the entire folder structure, select
base.wz and open it with Winzip, WinRAR, 7Zip or whatever file compressing tool you have, and extract it - it's just a packaged .zip file (uncompressed for obvious reasons such as loading procedures). Howeverm as you're just adding a model and not modding more complex stuff, you can go with
mp.wz and, after you've put your stuff on the right folders and packaged your .wz, run it as a global mod.
To see how to run a mod, you can just search the
FAQ section.
If you're just replacing the mesh and adding new textures, you won't need to change piestats.wrf, you'll just need to modify vidmem<X>.wrf files (read that "all of them") and frontend.wrf, if I remember right. you'll have to search for the model you want to replace within <extracted mp or global folder>/components/weapons folder, can be a tricky trial-and-error procedure again.
After you think you've done everything, just select you file compressing tool and
storage it as a .zip files and rename it to ".wz", placing the package in the <install folder>/mods/global and properly modifying the shortcut (this last part should be covered in the FAQ).
Go testing it. If it crashes, read the <install folder>/stderr.txt file and discover what's giving you problems within the "crash" lines (last ones for obvious reasons).
Try opening any of the game files with notepad to see what they're about - it's not that hard once you've seen most folders, their respective files' names, and went through a bit of trial-and-error (that's unavoidable when working with warzone).
Hope that this helps you a bit! Always remember to make a backup of any files you modify, and compare their patterns on notepad with the pattern of the original ones. If you put an effort on it, you can do it - even I managed to make a working mod (with help from a lot of nice guys, of course).
I can send a more specific how-to that
Mysteryem made for me, it describes more deeply the file types and folder structures.
Going in small steps is your best bet as the game's structure is very fragile and will work only with precise modifications. It's a good and bad thing because it'll make more obvious that you should change something, but won't allow you to see everything that's already right.
Good luck
~Olrox