I just got this game and I don't know what to do. I've just gotten the..

Go to Molida Island which is near the west of the southwestern sea-chart. Once there, a guy in a hut "near the village's edge" may be able to help you...

You could do what that guy is saying or since you have the cannon you can just shoot the tornado twice and it will go away and you get a rupee too

What you do is go to one of the isles (i forgot...) and you go to the hut to the very top right corner of the map. Talk to the guy inside (he should be mad) then go outside and talk to the women in the "garden" then go back and talk to the guy inside. He'll tell you about his dad's secret hideouts. Go in the cave behind his hut. Once you find his dad's first secret hideout (you should get the shovel), go back to the hut and talk to that guy. He'll tell you how to find his dad's second hideout. I'll just tell you how to open it because it takes too long. Walk on the rocky path outside the "garden". Keep going until you reach the first palm tree. Dig right in front of that tree. A hole will appear then jump into it. Look at the map and draw the route on your map. Follow that route in your boat. That's how to get past the fog. To go into the NW, just go west of the SW map until you pass the rocks then go up!