Chrono Trigger/The Hero Appears

Chapter 10: The Hero Appears(600 A.D. second time)

Head through Truce Canyon once you warp in, you'll notice the monsters changed since the very first time you visited it. Talk to the townspeople to learn about the legendary hero, and go to Zenan Bridge to learn they need supplies.

Head through the forest and into the castle.

Defending Zenan Bridge
Talk to the people there to find out the king was injured fighting Magus' army, then head into the kitchen and talk to the chef. He'll give you some jerky for the soldiers on Zenan Bridge and a Power Tab for your troubles. Take the jerky to the knight captain on Zenan Bridge and offer to help him to get a gold helmet.

Fight through two battles of skeletons, both groups very strong against physical attacks, so use similar strategies as with the Heckran Cave. Heal up, and get ready to fight Zombor. His body is immune to ice and his head is immune to fire. I generally have Crono use Cyclone to attack both parts, and everyone else use their best magic. Keep everyone's health above 50 if you can because it does some nasty attacks later on, and its last move before it dies is to drain the MP of the last player to attack it, so make sure you rest in an inn soon.

If you remembered to grab the Naga-ette Bromide in the cathedral in Chapter 3 or feel like going back for it, go in one of the residences that has a glowing blue dot shining a drawer nearby. Try to open the drawer, then talk to the old man to trade your bromide for a Magic Tab. Head south to Porre, stopping by Fiona's villa if you want, and go in the Porre market to find a power tab on the left side. Head into the Cursed Woods if you like too. If you attack the snakes they'll eat the frogs to restore health, which is handy since the snakes have lower defense. Frog will claim he's no hero, and won't be able to help you.

Denadaro Mountains
When you're ready to move on, head off into the mountain range. You'll probably want Lucca for this part, since like someone in the town told you, if you meet a goblin with a hammer you can burn the hammer to make it a lot less dangerous. It's essential to lowering their defense and attack. So you've got Lucca, Crono, and either Robo or Marle along for healing purposes. In the first screen, talk the exit to the right of the later to find a chest with a miragehand for robo partially obscured by leaves, then go back to take the ladder to run into Tata, the "legendary hero". Incidentally, as soon as you run into Tata you'll officially be in the "Tata and the Frog" segment of the game, so time to mosy into the next chapter.

Challenging Lavos
While the save file still reads, the Hero Appears, head to the Millennial Fair if you want to fight Lavos at this point and get The Tata/Legendary Hero Ending. This ending is a funny little one where Tata goes off to challenge Magus singlehandedly, convinced he's the legendary hero.