POST contact data from MSSQL Server DB to REST API, via C#

Question

Referring to http://www.c-sharpcorner.com/UploadFile/4b0136/implement-Asp-Net-web-api-2-in-Asp-Net-mvc-5/ ,

how do you modify the App to retrieve values from MSSQLServer database (instead of using static values in StudentApiApplication.Models) ?

How do you upload (POST) contact data (not using a file) from MSSQL Server database to WEB API & REST API, via C# or .NET  ?