Correct way to query data

I am create a custom notes extension and wanted to confirm the correct way to query and manipulate date.

I am looking at the docs on the side widget extension but there are some things I want to check

  1. Are you supposed to use records list to query data? Or can you use apollo directly?
  2. How do you know the mappings/module name to use?
  3. Is apis the the only way to post data?
  4. Is there more in the docs on this?