You use the mouse to move around the map, uncovering a handful of monster lairs and disposing of their inhabitants before encountering the monster boss. Once the boss is defeated you can explore the next section of the map.
Take a moment to grind the lairs on the first map section, partly to acquaint yourself with the unusual control scheme and partly to accrue enough gold for better equipment.
Give it 30 minutes or so and you will actually have a ginormo sword.
Ginormo Sword [Babarageo]