Whoever interested in pivoting to .NET Core career from good old .NET world should understand .NET Core programming model is bit different from .NET paradigm. Of course, .NET standard comes to rescue. However, ASP.Net Core internals and other cross cutting concerns like Authorization, Authentication, deployment are handled differently in .NET Core. And also, new things like Open API specification elements like Swagger and Docker Container support, support for external authentication provider and Azure support are natively supported in .NET Core system.
For a seasonal .NET developer, all the new cool things enumerated above may make them to scratch their heads when all they know is building .NET apps hosted on IIS running on a on-prem windows server with neat little custom login.
No sweat, Channel 9 comes to your rescue. You can learn the ins and outs of building ASP.NET Core application and understand the internals of .NET Core. See below series of Channel 9 which provides you a neat overview of .NET Core important modules