Infinite Void #1: After defeating the Commander and entering the new area afterwards, walk to the right hand side of the large statue in front of you, and you will see the entrance portal to the Treasure Chamber. In order to complete this Infinite Void, you must follow the light orb to the chests for you to open and receive loot from. The orb will stop at a location, and you must step on the pressure pad under it for the orb to continue moving. The orb will move around a couple of times. Once it has finished, leave the Infinite Void via the portal in which you came from.
Infinite Void #2: After defeating the Beast, the Portal outside the Graveyard and the entrance to the Rhogar Realm will open up. This is the entrance to the second infinite void. Once inside, you must follow the light orb around in order to prevent being poisoned by the green tiles on the floor. Eventually, two enemies will spawn. Quickly kill them or keep running around. The light orb will soon go to a chest. Open the chest, kill the two enemies, and then leave via the portal in which you arrived from.
Infinite Void #3: After defeating the Guardian, enter the room on the left hand side of the arena (where the spellcaster is located). This portal will be located in one of the three rooms. When you start, this Infinite void head to the campfire area in front of you and kill all the infected. I found the best attack is to run and then do a heavy attack. This will hit multiple enemies at once. Once they are dead, follow the light symbols on the ground to the area where you will get shot by a spellcaster. A ring of fire will develop around you. If you get knocked into it, you will die instantly. Use the same attack method to quickly kill the spellcaster and the shielded enemies. Once the enemies are dead, open the chest that appears in this area. Head back to the campfire and kill the Tyrant (his heart is located just to the right of the campfire). Now follow the light symbols in the opposite direction and open the three chests. A fire demon will spawn. Kill him and then return to the campfire one last time to open the chest that appears there. You can now leave via the portal in which you arrived from.