How to link table and joins to get exact warrenty contract from depot repair

I would like to know which table need to consider and what will be the joins which help for

1. To get exact RMA line details from depot repair.

2, To get exact instance id from installbase of the serial number present in RMA Line.

3. To get exact warrenty contract from serial number present in RMA Line.

This basically required to prepair the reports to understand warrenty details of any serial number belongs to RMA or ship line.

as most of the time instance becomes same but based on inventory transcations system generates different warrenty contracts every time for same serial number.