First, please stop being a dick; it’s unwarranted.
Second, here is what I see in the rulebook (located here).
p.4 - “Shuffle the Event Card decks for each age separately. Place the Event Card decks for ages II-IV aside for now. For your first game leave out Advanced and Expert cards. See more on page 11.”
So this just says to leave out Advanced and Expert cards for the first game. It does not say anything about substitution when you do use them, and I would say, implies that you just add them in later (as opposed to substitution).
p.5 -“Shuffle the Progress Card decks for each age separately. Place the Progress Card decks for ages II-IV aside for now. For your first game leave out Advanced and Expert cards. See more on page 11.”
Pretty much the same thing that was said on p.4.
p. 11 (“For your first few games”) - “Even if you are an experienced gamer, it is still highly recommended to start your Nations career with the basic card set. Using all cards will create interesting swings in card distribution that can be very difficult for the inexperienced Nations players to master, even if you are a very experienced gamer.”
Again, I do not see anything there regarding “substitution,” it just says to only use the basic card set in the beginning.
p.21 - “o With beginners, use only basic cards, the A-sides of the Player Boards, play with 3-4 players and take no worker the first few rounds. o With advanced players, use basic and advanced cards, play with 2-4 players. With expert players, use all cards, play with any number of players.” (Emphasis mine.)
Also from p.21 - The advanced and expert cards add more interaction, variation, and new concepts. After a few games with basic cards you can add the advanced cards, mixing them in with the basic cards. After a few more games you can add the expert cards."
Perhaps they should have added “mixing them in with the basic cards” after the reference to expert cards, but I think it is fairly clear they mean add the expert cards to the advanced and basic cards.
That was about all I had time for before I got tired of trying to find something you are asserting (that it talks about substituting cards) without further explanation or citation from you. (I also searched the document for “substitu” and nothing came back.)
Perhaps you could point out specifically where in the rules, with the accompanying quoted language, you believe it says you should substitute cards? I’m happy to believe you, but really do not see what you are talking about in the actual rules. I admittedly might be missing it, as I do not really want to re-read 24 pages of rules for something that you are asserting without much more to go on.