This example will show how to create a Data Entity to export all Vendor Contact informations like emails and phone numbers.
First create a Data Entity (to do this read my article : https://d365ffo.com/2021/06/29/ax-d365fo-create-a-data-entity)
Then you have to insert Table Data sources and link them together :
Synchronize database and Build the solution
Now you have to Refresh data entity to make it visible in Data Entity framework in D365FO. (read my article : https://d365ffo.com/2021/06/29/ax-d365fo-create-a-data-entity)
To export the data entity see my article : https://d365ffo.com/2021/06/29/ax-d365fo-export-a-data-entity/