Since this is your first stop before reaching the capital, you have several things to do in this peaceful, beautiful town:
For starters, I suggest exploring the town in the order described above. The treasure chest locations are marked in the map above. The Weapons shop is in front of Welch's lab and it's strongly recommended to fully upgrade your arsenal now.
Once done, enter Welch's Lab to trigger some Quests:
If It Tastes like Blueberries, It Must Be Good for You
Welch gives you this sidequest the first time around which will simply require you to bring 5 blueberries. You should have enough in your possession (unless you used them). Otherwise, you need to buy them from the berry shop west of the town. Completing this quest will unlock the Creation menu and unlock the Compounding specialty. This specialty will allow you to create various potions and concoctions. To trigger the other Quests from Welch, simply leave the lab and return again.
Drunk on Creation
For this quest, Welch will require you to bring her a Lemon and Spring Water. You can get two lemons from the chest in the docks in the middle of the town and spring water can be bought from the merchant in the marketplace. Hand her over the Materials and upon quest completion, the Cooking and Fishing specialties will be unlocked. Make sure to spend some SP to activate them.
Brute Strength of Blacksmithing
This time, Welch will ask you to bring her x3 Iron and x5 Wooden Sticks. You should have enough Iron in your inventory, if you managed to loot the chest containing the same amount of iron in Passage on the Cliffs. The wooden sticks can be bought from the Materials merchant in the western side of town. Completing this quest will unlock the Excavation and Fishing specialties.
When you're done with the Quests and upgrading your stuff, head back to the inn and you'll come across a somewhat familiar woman. Continue inside the inn and spend the night. You'll be woken up by Miki in a cutscene. After that, leave the inn and head to the west gate of the town.
There, you'll find Victor talking to another interestingly-dressed character. Approach them to trigger a conversation. Once done, both Fiore and Victor will join the party. After these, you can check your equipment, roles, and supplies for one more time then leave the town to reach the Resulian Plains.