As I mentioned in title, I have a huge WEB SİTE PROJECT, and I want to add MVCinto it.
I have followed some tutorials about it but all of them are about integrating
Converting the whole Web Site to a Web App (WAP) is likely to be painful, so I don't suggest it. You can try the other suggestion from @Grievoushead of making MVC work in a Web Site project (which can work), but I'll suggest an alternate one.
Instead of trying to 'merge' the Web Site and MVC WAP, try keeping them mostly separate, but sharing the same folder. You could do something like this:
A bit unusual, but depending on the exact situation, this may be a good approach.