Active Directory Authentication with separate Admin user

I'm working on my first Laravel project and have Active Directory Authentication successfully up and running using Adldap2-Laravel (https://github.com/Adldap2/Adldap2-Laravel).

I want to create a user with the username 'admin' and a predefined password that I can also use in the application. This user 'admin' is not part of the Active Directory Authentication, but I intended to use the same "users" table to store the credentials.

The intended usage situation is as follows:

1. The user reaches the Login page.
2. If they login with the 'admin' username and correct password, then a list of all "receipts" records are shown.
3. If they login with their Active Directory username and correct password, then a list of "receipts" records for that particular user are shown.

I'm not sure how to make (2) from above to work properly. How do I allow the user to login as the 'admin' user (not on Active Directory), or as their Active Directory username.

All help would be greatly appreciated.