survival mode

In this mode your kid will need to work to get everything in the game. This starts with punching a tree, which gives you logs. These logs can then be "crafted" (from your inventory) into planks. There are several types of planks including, oak planks, birch planks, and more. It all depends on the type of tree you punch. (Oak is most common). Now after you have planks, these can be turned into many things:

crafting bench (for more complicated recipes)

sticks (for crafting tools and stuff using the crafting bench)

and more

now in this mode in "night time" (every 10 minutes) basic "monsters " come out. These include zombies (pic 1), skeletons (pic 2), spiders (pic 3), creepers (pic 4), and a few others. As you can see from the below pictures, these are not very scary.

(note these pictures are different sizes, the monsters themselves are about the same except the spider (pic 3) which is smaller than the other 3)

These "monsters" will try to attack you if you are in survival mode. (In creative mode they leave you alone). You can fight them back by "hitting" them with whatever is in your hand. Items like swords will deal more damage to them than your fist. Different types of tools will do different amounts of damage (eg. iron sword will do more damage than stone sword).

On your first night, I recommend not fighting them and just going under ground and making a bunker/mine.