It's Impossible dude you're wasting your time.
War3 Model Editor EDITS previously-made models, which means : you change shape, texture, animation ... etc. you CANNOT make your own model using Magos' Model Editor (War3 Model Editor).
If you learn 3D Modelling using Autodesk 3D Max studio, or Blender, or Maya Studio, or XNALara, and learn animating, then learn converting, then learn texturing... you will be able to create an entire model. But that's barely possible, it needs just months of learning from tutorials and people. To motivating you, I advise you to continue over tutorials. I suggest Blender 3D Studio program to make 3D Models, and you can convert directly to MDX and easy to texture by this program.