Before you can save your work, you need to activate Isadora 3 with a valid Isadora 3 license.
You can find out more about the various Isadora 3 licence types, and purchase a license, on our Get It page.
Once you've done so, your activation information will be sent in a separate email. Then, once you've received your activation information, follow these instructions to activate Isadora 3.
Once complete, you will be able to save your work, and all Isadora 3 features will be enabled.