# Make sure you're on the right branch
# Then do this:
# Replace X with the number of commits you've made

git reset --soft HEAD~X

# Now, for the files you want in your final PR, do this:
# Replace path/to/the/file.xxx with the actual path

git add path/to/the/file.xxx

# Now commit the result:
# Replace COMMIT MESSAGE with something meaningful

git commit -m "Commit Message"

# Now push the result to github's copy of your repo:
# Replace your_branch with the actual branch name

git push --force origin your_branch