ASP.Net Core 5.0 Authentication and Authorization

I am quite new to Blazor and I am trying to understand authentication and authorization. What I did so far is reading the docs Authentication and Authorization in ASP.NET Core Blazor and Rolebased Authorization in Asp.NET Core. I managed to get authentication running, but I am struggeling with authorization. I would like to store every windows user who is visiting my server side app in a database and say User1 is Admin, User2 is Editor etc. and showing users diffrent areas of pages.