Car Rental Demo in ASP.NET MVC5 Razor Error

I have error in Car Rental Demo in ASP.NET MVC5 Razor. When I’m training to create new timeline I can’t do it


Hi,
please tell what the error is, I can’t see it on your screenshot

Hello I am the general manger of 2 rent a car companies, ganxorent and si-rent, I am really interested in adquire the car rental programm. Where can I get this info from?