It's tricky but you can do it if you listen to what Cid says. On the other hand, I have no idea how ANYONE is supposed to figure out how to breed chocobos using in-game clues. Even the chocobo sage is EXTREMELY vague on the details of this, and you'll have to spend hours figuring out which chocobos come from where unless you're using a guide. OR you could just beat Ruby weapon, which is REALLY fun when you don't have Mime, which you need a gold chocobo for.