I would recommend following this tutorial to see how to create a custom login page: Create an App with Advanced Page Building.
Once the user is logged in, you can grab the current user object to show any details specific to that account.
Create a custom login page by right-clicking your module, adding a new page with the login field with the password fields, and retrieve the current user from the account. I have attached the screenshot for your reference.
You can go with this module for step by step explanation.