Health, Stamina, and Mana.

In this guide you'll find the basics as to your three primary character resources, Health, Stamina, and Mana.

Health

Health, represented by the Red circle, is your vitality, or a measure of how alive your are. If you reach zero or less than zero health you will enter one of the death scenarios of the game, or alternatively if you are playing co-op you'll enter a downed state.
Health can be restored by resting, or using items. (Most notably Health Potions.)

Health will be burned (Maximum decreased) every time you take damage or use certain items.
You can restore burned health by resting, or using certain items.

Stamina

Stamina is a measure of how tired you are, many physical actions decrease your stamina, and your walk speed is tied to your current stamina.
Stamina can be restored by waiting, resting, or using items.

Stamina is burned by strenuous actions, such as attacking or sprinting.
Burned Stamina can be restored by resting, or by using certain items.

Mana

Mana is the magical resource, a measure of your ability to manipulate the world. This resource is not unlocked by default.
Mana can be restored by resting, or by using items.

Mana is burned by resting, but can only be burned to 50% of its maximum before the resting burn caps out.
Burned Mana can be replenished by using certain items, going an extended period without rest, or using spells.

End note.

I'll be updating this guide whenever I hear or find something of note, but this should cover the basics for anyone wondering.

[Knight]

Thats true, but if you're playing any sort of caster build, or even a spellblade waiting for your mana to regenerate between sleeps, can be a massive pain without items

[Corverean]

@Rook That depends on the build you're going for, because the max amount that mana can be burned is to 50% it can be cheaper to just sleep and recharge between encounters and sell the potions anyways.

[Knight]

its better to use items to restore mana than it is to sleep, sleep only gives you half your mana, with the other half regenerating really slowly after you wake up. A good way to make money early game, before you get mana, is to buy the components to make astral potions, and then sell them back for a profit. For pure cash money return, make warm potions, three of the four vendors in cierzo, sell oil, all you need to make warm potions is oil and water.

[Wild0ne]

There are 3 types of teas made from either seaweed or one of the 2 beetles you can get from gathering/mining. each one replenishes a different stat, it will tell you in the description. One cheap way to heal is to eat meat, cooked eggs or use bandages. A cheap way to regen mana is to eat cooked fish/shrimp

[Corverean]

@SOLID Updated the guide, you can restore Mana by resting, or by using items.

[Willie Nelson]

how can i reload mana?