Right-click the App_Code folder and then click Add New Item. The Add New Item dialog box is displayed. Under Visual Studio installed templates, select the LINQ to SQL Classes template and rename the file Tasks.dbml. Click Add.
Under VS2102, in your solution explorer, right click on your project, and select "Add/New Element".
Then you find : C# -> Data -> "Linq to Sql classes" (depending on your Visual studio version) or you can select "Entity Data Model". An assistant should appear to guide you through the rest of the process.
In your project classes you should then use your dataModel, and use Linq to make your requests.
if you want to reproduce, please indicate the source:
Getting started with linq-to-sql – Installation or Setup - CodeDay