Aug 02, 2019 07:37 AM|PatriceSc|LINK
The link I posted is using ASP.NET Web Forms and C#.
For now I believe you are more interested by actually creating a Web Forms app that allows to CRUD data rather than with general OOP concepts ? If you need further help please perhaps a bit more explicit about your exact goal.
If starting learning you could also look at ASP.NET Core and WebPages and/or MVC...
Of course OOP is related as the language you are using implements that but IMHO it can be learned separately....