We shall see each other soon, but i am appearing in your dream so i can teach you the basic of the battle. This will be quick and easy, so just trust and follow me. There's even a gift for you when we're done. First, i'll show you how to move. You can use the stick to move freely from left to right, top to bottom, and diagonally. However, you'll be attacking after moving towards the enemy by default, so move at your own discretion.
Press the boss challenge button. The conditions for making an attempt to kill the stage boss depend on the stage number and the number of monster. For example, if you're in stage 27, you must kill 27 monsters in order to make an attempt at the boss.
Now, press the Grow button. You can enhance a certain stat by pressing the button for it. It seems you have what it takes to become a great sorcerer. Now that you're grown stronger, let's take a shot at the boss one more time.