There is no Mac version of the game; however, folks have been successful running it under software that lets Windows run on a Mac, like Bootcamp (I think that's the name).
In order to process or craft something, you have to be next to the appropriate crafting station. Then open your skills window to the first tab, and pick what you want to do. Of course, this implies that you've learned how to do the particular crafting skill in the first place.

Humans can learn the skills in Pioneer Village and Logar, and Elves in the Valley of Preparation.