C# .NET Core 3.1 - adding functionality to an existing project

Good day,

I have a partially working application in c# on .NET CORE 3.1 in RAZOR PAGE's based on MSSQL.

I would like to add functionalities to it:

(a) dictionary of users ( first name, last name, login, password, email )

b) functions of logging in and out, editing the data of your user ( those above - name, surname, email, change of password ).

c) dictionary of user groups ( name, description, user assignment )

d) access to subpages (Pages) depending on either the group or a particular user. Some PAGES without having to log in.

e) OPTIONAL - the ability to identify the SQL session of each user through (SPIDD). At the moment the app connects one user to the database, SPIDD always the same.