This is your first quest on Sanrio Land and in Sanrio Harbour. After arriving on the harbour, you can see the white-and-black dog Pochacco dancing around not far from your starting position - in front of a house on the harbour that looks like a very colorful dog somehow.
You should be able to see the exclamation-mark ! hovering over Pochaccos head.
Walk up to Pochacco and talk to him by right-clicking on him. He will talk to you too and after affirming his speech, the quest-window as shown above will open. You should accept the quest by clicking on the green button if you want to experience the story of HKO and free the sleeping NPCs. Better accept every quest from now on for this purpose; only the 3 Pet-Hunt-Quests and the alternative house-quest from Thomas are really optional.
As the quest-text states, Pochacco wants you to meet the NPC Sora to get dry clothes from her.
Search for her by opening your area-map (by typing "a" or clicking on the minimap-symbol looking like a sheet in the right upper corner of your screen). Place your mouse-cursor over the green spots to see the names of the NPCs. Then walk to Sora and speak to her by right-clicking on her. You will get your next quest by Sora immediatly after talking to her.
You will also get green shorts and a top by Sora. Right-click on them in your inventory to wear these new clothes. Clothing boosts your defense in case of attacks (or counter-attacks) by creatures on Sanrio Land. As you will have to hunt some of the peaceful creatures in Sanrio Harbour soon, those clothes will be of great help.
You will get better and better clothes while your journey will continue through more dangerous areas. Some by questing, some by crafting, some from ingame-merchants if you buy them, maybe some by other players, by events or via item-shop. But you will only be able to wear clothes that have the same or a lower level than your character! Keep this in mind before selling old clothes and buying new ones that you might not be able to wear...
.You come to play in Sanrio land. You walk straight and you see that Pochacco have a quest for you. He asks if you want to go to Sora. Sora is in the southwest of Sanrio harbour. If you're at it you get your reward. Then Sora has a new quest for you.