Welcome back.
Create the account
Switch to Sign up and register with the approved admin email address and a password of your choice.
Verify your email
Check your inbox for a confirmation link and click it to activate the account.
Sign in
Come back here, enter the same email and password, and click Sign in.
Open the admin dashboard
Go to /admin — you will have full admin access automatically.
Tip: an existing admin can change this address in Admin → Settings — no code changes needed.