Git Trouble

I have a local project, which is located on Github. I want to push changes to the remote repo, it’s not working. Does anybody know how to push the new data.py file to GitHub?

    cd sea_spray
    git init
    git add .
    git commit -m "first commit"
    git branch -M main
    git remote add origin https://github.com/johnbarrett/sea_spray.git
    git push -u origin main

When I do this, all I get is: “fatal: remote origin already exists.” This happens with the command:

git remote add origin https://github.com/johnbarrett/sea_spray.git

Thanks so much for any help