For the base outfit, start by playing through shu's story until you can select zhuge liang, then check your gallery from the main menu to see what's available. The most straightforward unlock is his yang costume, which shows up naturally in the gallery once you've made enough progress. Moving into origins, you'll want to make it to chapter 3 where joining a faction gets you that special luan's wing look - its actually one of the easier ones to grab.

Getting into the older games is where things get a bit more involved but pretty interesting, since you'll need to clear through musou modes to see all the options. If you're playing xtreme legends specifically, maxing out those character stats and collecting everything opens up some really nice tactics-themed outfits. Something worth keeping in mind - a lot of the newer fancy costumes are tied to dlc packs nowadays, so check the store before spending too much time hunting for specific looks.

Once you've actually got the costumes unlocked, swapping between them is pretty simple through either the gallery menu or by stopping at any hideaway or inn depending on which game you're playing. The game usually lets you know right away when you've earned something new, so keep an eye out for thosea notifications while you're progressing through the story.