The final five appears probably in the first season. It is not immediately known what these characters are and what they mean. So from the season 1 finale to the series finale episodes - quite a move to build a mystery and then neatly explain it. There is nothing by force here. From the beginning of the series, it is part of the entire plot.
Did you see "Let's kill Hitler"? It's in season 6. In this episode, the relationship between the Doctor and Doctor River Song was the most poorly explained, especially since their story actually begins with that

Although they met before. But, if you are still watching the series, this season 6 will give you plenty of answers regarding the identity of Dr. River Song. Moreover, I think even this weakest episode is an introduction to a larger story related to the start of Season 6. Yeh, from trying to grasp the plot of "Doctor Who" it can make your head go awry
I always try to suit my clothes to my company. It is the only way to be inconspicuous.