Explanation:

Step 1: Synchronize the database
Entities are created as views in Microsoft SQL Server, and staging tables are also added. Therefore, you must sync a database when you build entities.
Step 2: Build the solution
Build your project
In Solution Explorer, right-click your project, and then click Properties.
Change the value of the Synchronize database on build property to True, and then click OK. This property must be set only one time per project.

On the Visual Studio toolbar, click Build > Build Solution to build the project.
Step 3: Configure properties for the data entity
After build visually validate and customize an entity
Reference:
https://docs.microsoft.com/en-us/dynamics365/fin-ops-core/dev-itpro/data-entities/build-consuming-data-entities