This sentence is connected to the last paragraph to say the benefit there is to studying CF for prerequisites. I think you still want to learn a prerequisite to learn CF, but learning CF helps with learning prerequisites too.
When it says this:
Does it help with learning a new prerequisite? Does it apply to prerequisites you already learned? I think both. I think that’s why it’s good to cycle between prerequisites and CF cuz it provides benefits to learning both.
You could just stick to learning CF to understand prerequisites better, but you might get stuck. You could also just learn prerequisites before learning CF but that might take a long time.