1. Open Terminal (cmd + spacebar; search for Terminal).
2. Move to the directory where you keep these files:

   cd ~/Desktop/[folder name]
   

3. Check to make sure all of the file you're changing show up:

   git status
   

4. If they are, you want to add them to staging:

   git add .
   

5. Commit everything you have in staging:

   git commit -m "Describe the changes you're making"
   

6. Push everything up to GitHub:

   git push