Hi Marcia,
You don't need to be associated with an educational institution. You can use personal Microsoft Account linked to Microsoft Learn (you likely have this already). Some of the sandboxes are currently unavailable with "The sandbox for this module is currently unavailable." message.
You can workaround the issue by opening up a new tab and activating sandbox using below link:
Once you have successfully completed the puzzle, accepted permissions, etc., and sandbox is activated, complete the tasks as described in Exercise - Explore the Learn sandbox. Additionally, you may leave the tab open and use the same sandbox for the Exercise - Create an Azure resource later in same module.
Please click Accept Answer and upvote if the above was helpful. If something is unclear or you need additional assistance please add a comment below.
Thanks.
-TP