The Project Versioning feature is great for saving and recalling different revisions of the same project.
To create a new project version:
Open your project and click on Project Details (left navigation menu)
Near the bottom of the overlay, click Create/Change Version
Name your new version and click Create Version
Please do not click away from this page while the version is being created.
The version that you just created will be the one that opens. You can switch back to the original version, or view an earlier version with the steps below.
To open a previous version:
Click Project Details on the left navigation menu
Click Create/Change Version
Select the version you'd like to recall and click Open Version
Hope this helps - let us know if you have any questions!