Restoring Original File

I started going through the Chapter 3 steps in Bihn's Bins to get used to the software. I did backups in the places the book told me to.

Now I need to go back to the original file for a project for the course I am taking.

The original file has all of my previous inputs in it

How do I get the original file back???

I need the file to be blank as it was the very first time I opened it.