Tutorial (not needed, it's pretty easy to get the hang of, but this explains everything if you want an in-depth guide):

In the Overworld, use W A S D to move around

Interact with things by running into them/on top of them

Spells in the right column of your actions are single use; casting them removes them from your spellbook

You can have multiple of the same spell

Arcane Bolt and Arcane Fusillade each reduce your Arcane Reserves (by 1 and 5, respectively), but are otherwise always available. If you do not have enough, you cannot cast them

Melee Combat deals damage and doesn't consume Arcane Reserves or spells, but you take damage in return. If you kill an enemy, you do not take damage.

You cannot return to a level once you leave

Click the "spellbook" button to see what spells you currently have

The keys found near enemies are used to open chests that contain more spells to add to your spellbook

There is a chest and key on every level

On the floor with the water/fountain, glowing golden orb which refills some Arcane Reserves (will increase the amount tomorrow), and also increases the damage of your two Arcane spells and melee attack

Also on that floor, there is a green blob-ish looking creature. Interacting with it will heal you, but will cause it to die.

Arrows point you towards the stairs and combat of a level