Login display information application

I have a simple microsoft access database. I have 4 tables.
1. user database with username and password info
2. parent data that has parent names and addresses
3. student data that has student names and grades
4. teacher data that has room number and homeroom teachers

I want to link a user name and password to a parent record to display all of the student data needed (teacher name home room student address etc)

The databases have relationships built in access.

I have a login page that works but I really dont know what else to do. Can someone point me to some information?