Not much to get. :) Minecraft..is a sandbox game. That means you can do nearly anything. If you want to be a builder---go build! If you want to be an adventurer--go adventure! If you want to do a mix of both..perfect!
You start out with nothing. Your first priority is to gather wood. Punch some trees (lol) and get wood to make a pickaxe! Then you need coal. There are plenty of videos online that describe how to start out.
But anyway, it's a crafting game. A block of wood will make wood planks. Wood planks will make wood sticks! A stick plus coal will make a torch. Wood planks in a box shape will make a box to hold your items. wool and wood when put together the correct way will create a bed. Meanwhile you can use these items like legos to build! Make a dirt house, a wood house, a floating house.
Light helps protect you from monsters that spawn at night. You will need to gather food to protect yourself from hunger! Survival is key in survival mode.
But there are so many ways to play. Some people ONLY mine. Some people ONLY build. Some people like to make a multiplayer map where they recreate a city!
There is also creative mode which is basically digital legos :)