A great way to learn how-to develop your own database is to look at pre-made databases. As such, below is a listing of database templates from various sources.
Microsoft

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UtterAccess
MVPs. Many MVPs have a slew of samples on their site, so they usually are a great place to look
Microsoft Access MVP Websites
Some of the most valuable websites (especially regarding Access of course) are those of many of my fellow MVPs (and a few other exceptional individuals). So I thought it intelligent to try and compile them here. If you are looking for some of the very best online resources, these are the sites to start with! …
Warning
Be careful which databases you use/base your work off of. Sadly, not all databases, even those coming from Microsoft, are designed properly. So you still need to ensure you follow development Best Practices to ensure a successful outcome!

Access Best Practices and Troubleshooting Steps
I thought I’d make a quick post to go over some basic Access development best practices and Troubleshooting steps that any developer should be aware of. MS Access Development Best Practices So you want to start developing an MS Access database! The following is based on my personal experience developing databases for over 15 years now. …
If you know of other, non-commercial template (ie: free with no strings attached) please let me know so I can add them to the list.