These 2 cards you can use it only in additional turns 5.1 5.2 ?????or whenever you want ((if you use it in first 5 turns you 'll lost the option for additional turns)
You can use them any time. Nothing in the rules about using oar cards suggests otherwise. The only reason the starting cards are mentioned in the section about extra turns is to emphasize that you will have only two extra turns in the entire game because you have two extra cards in your hand.