This will make a copy of the repository on your Github account.
It is important to do this step first, or you won't be able to save the changes you make to the code.
Remember:
This is a button on the github website up in the right hand corner of the repo you want to copy
2) Clone the repo FROM YOUR ACCOUNT, NOT DEVMOUNTAIN'S ACCOUNT (or any other account that you are copying repos from)
This downloads a copy of the code onto your computer. Then, when you commit your code you can push the changes up to Github to be saved onto your account.
If you forget to fork, or if you fork but forget to clone FROM YOUR COPY you cannot push your changes to Github and save your progress.
Remember:
git clone [url of the repo here]
Work on your project and remember to commit often.
Remember:
git status
git add [whatever files you want to save]
git commit -m 'I AM A MESSAGE'
When you've made good progress or you've finished with your project, you're going to push your changes to github.
Remember:
git push origin master
You can push as many times as you need to. I would recommend commiting (see step 3) several times a day, and pushing once or twice (when you've finished a significant junk of code)