RE: Run Report on Selected Record
Hi Bahalzamon,
In the main view, you can select reports that based on current entity to run.
You said: select the report and have it show me a basic report of its related records.
--If you want to show the report of the related entity n current record, you can open the form of the record, then navigate to related records view, there is one 'run report' button:

--If you insist on run report of related records on the main view:
You can configure one report that based on primary entity, then select related entity at the same report:

Please refer to my previous answer in the following thread: