ASP.NET Core MVC Two-factor Email confirmation without Identity

i'm using ASP.NET MVC Core and i'm not using ASP.NET Identity.

Now i want to implement a email confirmation mechanism for the user's sign-in process.

The problem is that all the examples that i could find in the internet are using the "AspNetCore.Identity.UserManager" class with its

_userManager.GenerateEmailConfirmationTokenAsync(userId);

and

_userManager.ConfirmEmailAsync(userId, code);

methods for generating and checking the confirmation token.

Since i don't want to use Identity, ¿how can i implement "email confirmation" without Identity?

Thank you.