Can you please give me a link to a tutorial you referring to?
Most likely it’s down to the definition of your model classes. The code of your page assumes they are declared under SchedulerNetAsp.Models namespace and there is
using SchedulerNetAsp.Models; command somewhere.
This namespace appears not to be declared in your app hence the error. You’ll need to check the definitions of model classes to see in which namespace they are actually declared.
They may be declared in the common project namespaces (SchedulerNetAsp), so the error may be fixed by simply removing
using SchedulerNetAsp.Models; from your code.
If nothing helps - please share some code or a complete sample project where the error can be reproduced