You'll want to start by completing those star objectives in the early campaign missions, because they're actually the foundation for unlocking these alternate paths (this becomes really important later). When you're playing through, keep an eye on those special officers who typically die in the historical route - keeping them alive opens up new possibilities.

The real turning point usually comes around stages 8 through 10, and that's where things get interesting. For wei's path, you'll need guo jia alive and well before chibi (fascinating how one person can change the entire course of history), while shu needs xu shu present at fan castle. Over in wu's campaign, make sure you've done everything needed to keep zhou yu in play at hefei.

Something worth noting - when you've met all the conditions, you'll notice the stage selection arrows turn purple instead of red (pretty clever way the developers show you're on the right track). You'll also want to chat with specific officers at key moments, because these conversations are what actually trigger the alternate paths.

A couple things that might help - running through earlier stages on a lower difficulty makes getting those star objectives much more manageable, and it's always smart to keep a separate save file before those pivotal battles (trust me, you'll thank me later). The game doesn't always make it obvious when you're working against a time limit, so keeping track of your objectives through the pause menu can save you some frustration.

If you're curious about the historical significance, these alternate paths actually show us some fascinating "what-if" scenarios, like how differently things might have played out if certain strategists had survived key battles. Keep that in mind while you're playing through - it adds another layer to the experience.