MS-Teams Graph | listing all callID's or the call history of a member | call duration

dear wonderful people ,

for a small intern project I want to implement the call duration of the ms-teams into the customer relationship management system database - I don't manage to list all  callID's to then get the startDateTime & endDateTime of the microsoft.graph.callRecords segment.

- what is the most convenient way to get the list of all user IDs of my organization?
- how do I get the list of all call IDs?
- how do i get all call durations or the call history of a member?
- how do I subscribe to an update for each call made by a user in the group?
- how do I write the session data to the database?

Thank you to anyone who can help me. I have been dealing with this for a while and am currently trying to find a solution with CQD and PowerBiConnect. Im willing to pay a pocketmoney of 100-150€ or more for a working solution proposal and the willingness for light verbal support if I can't get the implementation right.

Greetings from Germany