Seems I'm always forgetting the git syntax for checking things into the repo...simply follow the steps below and you should be alright.
// before you make changes to your local git dir..
git pull // to get you in sync with the main repo
//write your file to the local git directory where you want it
git status // this will give you an idea of the changes
git add path/to/new/file
git commit -m "some witty comment here"