...

Once she feels like her code is ready for review, she will squash her branch using an interactive rebase.

git rebase -i 

This will open her editor, allowing her to choose which commits to squash.

pick f33b240 Add some commit
pick 73bbc09 Add some other commit

You can choose which commits to squash by changing pick to squash.

Then, she will commit and open a Merge Request, and put her opens a pull request and puts the code up for review. A  A Software Lead will work with her to review the code, and she'll make any changes, and add them to the review. Once this is approved, the changes can be squashed and merged.

TL;DR

1. Create feature branch
2. Perform development in feature branch
3. Routinely push commits to remote tracking repository
4. Squash commits and put Put code up for review
5. Squash and Merge into master