Ok, so you should have your model already made, right?
if so, then continue.
First, what you want to do is make a new folder in you models directory, and for this case, we'll name it "test".
(models directory is usually in PlatinumArtsSandbox/packages/models)
Put your model in there, and make sure it is called "tris.obj"
Then, open notepad and type in this:
Then, once you save it, click where it says "Text Documents (*.txt)"
Click "All Files (*.*)"
Name it "obj.cfg".
Then, save the cfg file and drag that to your model's folder.
Once you have done all that, drag your model's texture file into the model's folder, and name it "skin".
Once this is done, launch PAS and create a new map.
Press your chat key, and type in "/mmodel test"
Open your Mapmodel GUI and click the last tab.
Your model should be there.
Then, you click it.
Hope this helps!