The following are the steps to connect LocalDB in Visual Studio,

• To connect to LocalDB in Visual Studio, follow these steps
• Open Visual Studio and go to the Server Explorer window.
• Right-click Data Connections and select Add Connection.
• In the Add Connection dialogue box, select Microsoft SQL Server as the data source.
• In the Server Name box, type (localdb)\MSSQLLocalDB.
• Select Windows Authentication as the authentication method.
• Click Test Connection to verify that the connection is successful.
• Click OK to close the dialogue box and save the connection.