Hi,

You can use the Community Edition of Odoo, which does not have an expiration date. Once you create a database in the Odoo Community Edition, it remains active and usable indefinitely, provided you maintain the server and database without interruption or corruption. However, you may face some drawbacks while using the Community Edition, such as limited features and modules, lack of support and upgrades, etc. Alternatively, you can take a backup of your Enterprise instance and restore that database using the dump file. This will help you learn the concepts you mentioned in an effective way. By doing this, you can continue your development without losing previously developed items.

Hope this helps.

Thanks.