step 1: accept the lab invitation you received, it will take you to the GitHub Classroom lab.
step 2: you will see a repository link form the lab assingment page, click on the link to open the respository on GitHub
step 3: clone the repo to your local manchine alternatively, you can create a new branch in the repo, or close to local machine or create a new branch on github.
step 4: create of modify the necessary files to complete the lab assingment.
step 5: after making changes, add, and commit then to your local repo and also push to the remote repo.