Append your name to the contributors list in the HTML file in the cloned repo and save the changes.
Add those changes to the branch you just created using the command:
git add .
Now commit your changes using the git commit command:
git commit -m "Adding my name to the list"
Push your changes to GitHub by the push command:
git push -u origin [BranchName]
Go to your repository on GitHub and you’ll see a button “Compare & pull request” and click it. Open a pull request by clicking the "Create pull request" button. This allows the repo's maintainers to review your contribution. From here, they can merge it if it is good, or they may ask you to make some changes. Please provide necessary details on what you’ve done. Now submit the pull request.
Congratulations! You've made your first pull request.