Getting it out of the iPad is easy, and you have a number of choices.
From the tutorial: You can also export projects by entering “Edit” mode in the sidebar, selecting a single project, and tapping on the “share” button in the toolbar at the bottom of the sidebar. This allows you to email the project as a .zip file.
You can also save it to cloud storage using this method. From the iPad, I export zip files all of the time to OneDrive, as backups while I’m working on the iPad.
You can then unzip the project and edit it on your PC.
But getting it back into the iPad is limited to DropBox or iTunes sync. Those are your choices.