Click the pickaxe, or the spacebar to mine. It may take more than one hit, but you only have to click once, it will swing a second time if needed. Click the open shop button to... take an educated guess. Same for closing the shop. You can buy a better pickaxe if you have enough money.
This is for @matteo0819 's Game Contest (GO FOLLOW HIM RIGHT NOW, THIS PROJECT WOULDN'T EXIST WITHOUT HIS AWESOME GAME CONTEST!!!) 100% code by me 100% images by Mojang Studios 100% image editing and modifications by me 95% ideas by me 5% ideas by @matteo0819 75% feedback by @matteo0819 25% feedback by my sister 100% of beta-testing by my sister 100% of credit to @jb0715 for telling me he is going to beat me in this contest (go check out his and comment that my project is so much better than his) 100% of game contest hosting by @matteo0819