need help in to add MasterPage into .aspx page in ASP.NET

Question

Sir,

 

I am in a asp.net mini project. My issue is with adding master page into .aspx page.

 

I added a master page, then an web form, but i cannot refer master page into web form. I cannot dynamically refer master page. this is the screenshot when i add a web form:-

 

 

 

 This is my master page :-

 

 

 

and I write code in page declaration part like this: MasterPageFile="~/Site1.Master"

 

Then in run, I getting the following error:-