Once the class files and related projects have been generated you must compile the solution before you can use it within your own application. You can continue to modify the object and property settings within ORM.NET as well as make changes to the underlaying database. You will not lose any previous work you have done. However, you will need to click "Generate Data Layer" and then recompile the latest version of the project each time for the changes to take effect within your application.
To compile the Data Layer Solution
Open the generated solution within Visual Studio.NET
Select the Build menu item
Select the Build Solution sub-item
The solution should compile without errors. You can now use the generated Data Layer component within your own application.
Go to Step 6: Develop your application to see some code examples which show ORM.NET's object model in action using the auto-generated TestApp project.
Refer to Integrate ORM.NET Data Layer within an application to learn which assemblies and files you will need to include.