The camp underground is a free space under your camp that serves for storing your camp equipment to produce energy that your Diggy needs in order to clear tiles in locations.
Since energy is a very important part of the game it is very useful for you a new player to learn as much as you can about how to do all the features related to energy work 😊
Any camp equipment that produces energy or expands the capacity of Diggy´s energy can be placed here. Also, you can always switch the camp equipment you have in the camp underground which means that if you don´t like how your camp underground looks or works you can always change that. The placement of the camp equipment items is not irreversible 😊
Now let´s look at how it looks like down there:
The camp underground can be accessed by clicking on the ladder in the middle of the camp: http://prntscr.com/pvy11n
The first thing to note is that the height of columns in camp underground is different – the shortest columns are situated in the upper parts of the camp underground and the height of the columns increases progressively as you go deeper to underground.
Regarding the height, there are 3 types of columns in the camp underground:
Height 2 columns:
Height 3 columns:
Height 4 columns:
This is given by the height of the camp equipment – the smallest camp equipment items are height 2, the middle ones are height 3 and the largest are height 4.
To move along the camp underground just click on the green arrows on the left side of the screen:

If you tap the bottom arrow: you will get deeper to the underground. And on the other hand, when you tap the top arrow you will get higher (closer to the top of the camp underground). To get back to your camp you can simply tap the double arrow icon here:

Have you tried to place camp equipment to the underground and figured out it is not possible?
Well, the fact is that when you start playing the camp underground is full of debris so your job is to clear the grids of debris in order to make space for your camp equipment.
Please be aware that in order to clear the grids you need to make sure you have enough resources since removing debris costs you materials or gems. But you will get some sweet materials in return!
If you click on the debris you will see that you have two options: you can either use your materials such as lumber and stone or you can use gems to clear the grid: http://prntscr.com/pvu5wp
Still having issues placing the item? Well, you are probably trying to place a camp equipment piece to a spot that is shorter than the height of the item you want to place.
In this case, please find a suitable spot that is at least the same height (it can also be higher) than the height of the camp equipment item you are trying to place. Then just clear the debris and voila! You can place the camp equipment piece now 😊
As you can see, orientating within the camp underground is not that hard. You just need to know some basic rules and you will easily get used to it 😊