Pick one of your past Full-Stack projects, fork it if you haven't already and add user authentication to the Back-end and Front-End.

Alternatively grab the backed Todos-Backend included in this repo and add proper Back-end user authentication with Passport. You might need to modify the database schema a bit. Make sure no todos can be retrieved from the back-end if the user is not logged in.

Build Front-End to access the Back-end with proper user authentication. You can use the Frontend folder in this repo to start off.

Adding user authentication is probably going to be different for everyone but the core will be the same. You might need to create a users table or add a column for the password etc.