Just make sure you have a pickaxe (old, iron, or mega [the best]) in your item pouch
Go find whatever piece of rock you find, go near. If you have a pickaxe in your item pouch, it will show the icon with a number. Then press A and you'll begin to mine. If you bought your pickaxe but if it's still in your safe, it won't work, make sure you have not bought something and directly sent it to your safe : At the shop, you can 'buy' or 'buy, and send to box'. If you've done the latter, that should explain why it isn't in your item pouch. Also if you bought old pickaxe, it will break very quickly, so buy as much as u can.
Good luck, it's sometime a bit frustrating coz there's so much to prepare before actually beginning a quest, it might be a bit overwhelming for a start.
