I apologize for being so late reporting this, but here are the controls in the game:
Game controls:
TAB: open the menu of the hero stats.
1-2-3: is the use of healing potion/ mana potion / rage (increases the damage/healing from all magic)
z, x - change the choice of magic (for each hand)
The Books are a save system. It restores the potions and completely your hp + mp. (like a campfire in Dark Souls)