Use the arrow keys to move Shin - holding the down arrow will allow Shin to sit and recover HP and MP. The W key lets you attack while the A key is an action button that will let you open and exit doors, chat with others, and just about everything else. Purchase and equip new weapons to increase your attack, and upgrade your stats when you gain levels in this linear RPG game.
Shinland is, as you guessed, about a protagonist named Shin - a wandering person who suddenly finds himself on an island. From there on, Shin finds himself fighting against a wide array of enemies - ranging from army ants to dinosaurs.
At least that's the basic storyline - Shinland borrows a lot from JRPG games - at least the art direction does. You'll notice a lot of cute weapons, accessories, and items, but when it does come down to fighting, things to tend to get bloody in Shinland.
You'll start the game outside of a small village, and you'll have to fight your way in. While doing so, you'll pick up your first weapon in the game, throwing knives, and you'll learn how to use them. Using weapons with the W key is easy - holding it down will allow you to attack in an auto shoot mode. However, using weapons decreases your MP, and although it may not seem like that matters at the start of the game, stronger weapons will decrease your MP much faster.
One of the most important things you can try to do in Shinland is pick up as much money as possible - although stronger weapons require a high charm stat to equip them, there's nothing wrong with having a nice stash of money on you at all times. Next, if you haven't noticed already, monsters are very avoidable - you'll only take damage when you're physically running into them. As long as you fight monsters from afar (after all, you are using throwing weapons), you'll be able to take on any foe in this RPG game.