Execute a git pull in your repository directory to download new files. Prompt files won't change after posting, so feel free to modify them as you like. Here once again is an informal guide to git.
To develop efficiently, have a local web server running. Python has a simple, built-in server. Use python -m http.server for python 3; use python -m SimpleHTTPServer 8000 for python 2 (execute python in cmd for version number).
To learn more about functions, check out this tutorial by John Resig