1. Ensure git is installed on your machine

2. Clone the repository (via terminal):

git clone [git url]
cd rle-pcb

3. Use php to serve the application locally

Ensure you are in the working directory pcb-rle

php -S localhost:8000

4. Navigate to localhost:8000 in your browser.

Before making any changes, make a new branch (git branch [branch name]). Then, you can edit and test via your localhost server.

Use any source code editor you prefer (preferably meant for HTML/PHP/CSS). Atom IDE, NetBeans IDE, Sublime IDE are all good choices.

Make any changes you want, add them for staging, and commit them.

git status
git add .
git commit -m "Message describing the commit."
git push origin [branch name]

Then, via GitHub, you can make a pull request for your branch and others in the team can verify/review the changes and merge them into the master branch.

This is the industry standard technique for making changes on projects such as this.