1: There are quite a lot downloads concerning model files on the conitec server so what do you mean in particular?

2: You want models for using them in your project so put them into your project folder or a with path linked subfolder if you want to have your folders in some order.

EDIT: To make that clear, if you just have model files, you can put them everywhere, you just have to show GS in your script where to search for them. This you'll do with defining PATHs.