This is assuming that you have already forked and cloned a branch in your terminal.
When you want to edit the code, follow these steps:
If changes have been made by Isaac, on your github page (for tardis_impact) it will say your branch is __ commits behind smithis7:master (if it says you are some number of commits ahead, contact Isaac). Next to that message, click on pull request. If it says there are no changes, you will have to click on "try switching the base for your comparisson". From there, click "create pull request", commit, and then click "merge pull request", and confirm.
In your terminal, type git pull origin
Do whatever you are trying to do with ads.ipynb and README--IMPORTANT_and_progress_updates.md (and save your work). Before step 4, make sure that your key is not in the ads.ipynb document.
When you are done, in the terminal, do git add ads.ipynb and git add README--IMPORTANT_and_progress_updates.md.
In the terminal, do git commit -m "message about your commit"
In the terminal, do git push origin
If you need to make more edits and Isaac has not edited since, skip steps 1 and 2.