Should you wish to build your instance from scratch without reconfiguring the VM and/or network settings, you can simply rebuild the instance from an image. Doing so means a fresh copy of the operating system of your choice will be re installed on an empty hard drive and the data on the main disk will of course be lost.
Next to the “Create Snapshot” button to your right you can see a small arrow pointing downwards; click on it to open the dropdown menu.
Now select “Rebuild Instance” from the bottom of the Drop Down menu.
Select an Image from which you want to “rebuild”. It can be a stock installation image of your favorite operating system or an Image you created yourself, for example an Image you created from a snapshot (Backup).
Select an Image and ...
... click on “Rebuild Instance” to start the rebuilding process.