This is an image of a typical keyboard–yes yours may not look exactly like it, but just pay attention to the colored keys.
Green: These buttons are how the player interacts with objects and/or people. This also makes the text on the screen proceed.
Orange: These buttons tell the character where to move. So obviously, if you want your player to move up, press the up key; if you want the character to move down, press the down key; et cetera.
Blue: Hold this button down if you want your character to dash. Otherwise, your character will be walking.
Yellow: Press this button to make the arrows on the map show up. Arrows show you where entrances and exits are and when you first enter a map, an arrow will show up above your character so you know where he is on the map. This feature is off until you press the S key. If you get tired of having the arrows on, press the S key again and the arrows will go away.
Red: These keys will open your menu and it will also cancel or exit.