I need a excel master for a single formula

Hi

I work for a tuition centre

currently there are 9 classes going on 4 times a day (36 classes per day)
Teachers need to produce a report

i would like someone to write a formula for me that

1. gives me the class ID
2. selects all the students for a specific class based on the teacher selecting some information.

Please note some teachers teach more then 1 session

I have already started it

so a teacher can select the session they attend, this auto selects the name of the lead teacher and the list of teachers who teach in that session.

the idea is when the teacher selects there name in cell B7

it should give me the class ID in cell B8 and produce a list of students in his/her class from cells B11 to C24

I have included a copy of the spreadsheet.

Thank you