Sounds good to me. Please feel free to add them. I don't know CLI git very well, since i've been using a git GUI
Sorry, but if I suggested to add them it is because I don't know very well how to do that.
I think that for the firsts commands it should be :
Create a new branch ---> git branch my_branch
Checkout that new branch ---> git checkout my_branch
Commit your changes to that new branch ---> git add modified_file1 modified_file2
git commit -m 'what I have done'
Push that new branch to your GitHub repo---> git push
but I haven't done add an origin to its git repository in order to track the changes on master nor any merge.