Add ASP.NET Core Identity to an existing project that has the database first model

Question

I would like to add ASP.net Core Identity in an already existing project, which already has many tables mapped with database first, also I should add a relationship between AspNetUserId and my table mapped to the model with Database First

example of integration between code first Asp.net core identity and existing tables (database first)

how do I create a relationship between the AspNetUsers table and the MyTable table (foreign key AspNetUserId), can I make the changes on the DB and then apply "Scaffold-DbContext" on the MyTable table ???