You do not need to know every rule before enjoying the Finals. Start by recognizing the event category, then follow the difference between a nightly result, the average and the season championship.
The round winner, average winner and world champion can be different athletes. They answer different questions about performance: who was best tonight, who built the strongest Finals aggregate and who finishes on top of the season championship race.
NFR qualification is the result of a season-long race, rather than a single entry event that anyone can win to reach Las Vegas. Understanding the standings makes the late-season competition and the announced Finals roster much easier to follow.