Hi @Arend,
Use Live Data means the IAL never stores data. It always queries the source tables at runtime, so the data is always current. There is no scheduling or copying involved, but it can put more load on the database.
Copy All Data means the IAL stores a full copy of the data. Each time the job runs (manually or scheduled), it reloads all records again. The data you see is only as up to date as the last successful run.
Copy Only New Data is an incremental load. It copies only the data that has changed since the last run, based on a timestamp or similar column. This usually includes both new records and updated records, as long as the source supports tracking changes.