Now you can obtain "Bottle with a Note" by spearfishing.
There is a chance of obtaining a treasure map upon opening a Bottle with a Note.
Right-click the treasure map to receive a treasure hunting quest.
Based on the quest content, figure out the location of the treasure and dig it up.
Hand over the treasure to Marzana in Ibellab Oasis to receive Sealed Golden Treasure Chest as a reward.
Use a Gold Key to open the Sealed Golden Treasure Chest.
I might prepare a guide in future. But right now for whom wants to do this quests, you can use google translate on your mobile and use live translate with camera.
Pêchée en AFK ici.
Compter une bouteille toutes les 2-3 nuits, gourou 9. Ne suis pas certain que l'on puisse pêcher une autre bouteille tant que l'on a pas fait la quête Dropped with AFK fishing here
Roughly 1 bottle every 2-3 nights, guru 9. Not sure we can fish more than 1 bottle until we did the quest inside