Oxygen
One of the most important thing for a living creature to live is Oxygen ! Without Oxygen, you die 😥!
Let's learn how to create oxygen !
The Machines
To create oxygen, you first need to craft the water separator. This machines separate oxygen and the hydrogen from the water.

To automate the water, you can craft a Water Pump over a water source next to water separator.
WARNING
The Water Separator and the Water Pump both need to be powered
(Don't mind the broken textures)
Use the oxygen
After that, you will be able to generate oxygen

In the left tanks, hydrogen is generated
In the right tank, oxygen is generated
To fill up an item with oxygen, you can place it under the oxygen tank. For exemple, you can fill Oxygen Tank or a Space Suit.
Oxygenate a room
Now, you have oxygen ! You can put this oxygen in Oxygen Tank.

You can fill this tank by putting it into the slot under the oxygen tank in the water separator.
After that, you will need an Oxygen Distributor

Place it in a sealed room with nothing over, and then put the oxygen tank in the middle slot !

WARNING
The Oxygen Distributor need to be powered