I like the book Programming Role Playing Games with DirectX (2nd edition) for its scripting section; I haven't really seen a start-to-finish tutorial on making a scripting engine elsewhere. And of course, being a book, it will walk you through step-by-step creating the scripting part of the engine (and the whole rest of the game engine that he establishes throughout the book, of course). Unfortunately the source code isn't available online.
Once you have a scripting engine, I would keep separate the 3D models from the scripts. Scripts are typically in the logic side of things, while 3D models are most certainly the presentation/view side of things, and those shouldn't really be mixed. When a script commands a character to "walk to (3,5)", it doesn't need to say "load walking animation, set velocity to (-1,1), wait 3 seconds, set velocity to zero, load idle animation"; you'd typically just have a
walkTo(x,y) function available to the script, and the intermediate code would take care of 3D models, animations, etc.
But hey, if you really need to, then define your own functions in your scripting interpreter which get 3D models and do whatever you need with them. I think you're thinking a bit too far ahead; worry first about writing a simple script interpreter, and then add the necessary functions to the interpreter as you're writing your scripts.