Accessing user and role data within an OrchardCore decoupled website

I am making my first OrchardCore based website using Razor pages, a decoupled one, where I access the content via the OrchardCoreHelper.

I do not know how this is usually done in this kind of site, but I intend to use the users and roles from OrchardCore for my website's authentication and permissions.

So I guess my question is a two-parter:

1 - Is there a way to access user and role data from the OrchardHelper interface and a way to get the current user from there?

2 - Is there a recommended way to use the admin login screen to login into the system and be redirected to the frontend?

Thank you all, hope these doubts are not too moronic.