I'm a beginner in Minecraft.
Question 1. What should I do in Minecraft? What is the goal?
Question 2. When I dig, I can only collect the material from the first layers. How so? Why can't I collect the material from the lower layers and what do I have to do to be able to do that.
1. Build your own world and end up defeating the end dragon in the end
2 In order to collect what you call the second layer of stone, you first have to make a wooden pickaxe.
What to do in Minecraft What is the goal?
The goal is simply to have fun. Build, farm, mine, equip yourself. You can also kill end bosses like the Ender dragon.
For question 2:
You need a better pickaxe.
With wood and gold you can mine stone and coal, with stone you can also mine iron, with iron then gold, redstone and diamonds and with diamonds and netherite everything - apart from Bedrock.
To question 2. You have to use wood to make a crafting table for a German workbench and then use wood to make a wooden pickaxe. You can then use it to mine stone.
to 1. The whole thing is a creative game you can do whatever you want. Most see it as a goal to achieve everything that works if that helps you.
The others have already said everything. I'm just asking. It's best to watch a beginner's Minecraft video. It explains a lot, which is only natural for people who know it.
How can I end up killing the Ender dragon? Does he just come to me at some point or how? What should I do at night when the monsters come? Waiting until the night is over is boring. But if I die, I lose everything, how can I prevent it?
In single player, the goal for most is to kill the Ender dragon in survival mode. This need not be. In creative mode you have all things and can therefore do everything, so there's actually no goal other than maybe to create a building.
There's also the multiplayer. There you can go to different servers and there are many little "mini-games" there, the goal is often to live with your team or alone as the last thing, which is caused by different factors, such as falling down and dying, (Bedwars, Skywars.) Is difficult. Other servers do not put so much emphasis on fighting and there you often have an extensive economic system, there the goal is rather to have a lot of money or a nice property. A large German server that offers something like this is gommehd.net. If you want to play in multiplayer mode, it is best to watch a video on YouTube on how to get one of these. (If you play on GommeHD.net and have any questions, feel free to send me a friend request, if you are interested, just answer this answer here and I'll tell you my name.)
Now to the other question. At the beginning you have nothing in the single player, so only the hand. You can only mine wood, earth, sand and a few other things with it, if you mine anything else, you won't get the item and it simply disappears. In order to mine stone (what is under the "first layer", the earth), you need a wooden pickaxe. For them you have to take down a tree, then make a workbench, sticks and boards. Then there's another recipe for this, from which you make the pickaxe. Sounds more complicated than it is. If you want to know how to do one of these things, just enter the respective thing in Google and add a crafting recipe, then it should come.
I would also recommend you to watch YouTube videos to see the first steps.
If you have any questions, feel free to write me.
I hereby officially answer the answer.
How can I end up killing the Ender dragon? Does he just come to me at some point or how?
You have to find it yourself. For that you need end eyes. For the ingredients, see here: https://minecraft-de.gamepedia.com/.../Enderauge
What should I do at night when the monsters come? Waiting until the night is over is boring.
Sleep in a bed and skip the night, or fight the monsters.
But if I die, I lose everything, how can I prevent it?
They stay there for 5 minutes where you died. Just run back and collect it.