What do I have to consider before downloading Minecraft?

Someone once said that I should download Steam to my PC beforehand or I don't need it if I want to play on a different device if I have a new PC

You have to download the Minecraft Launcher from the Internet and with your account you can also play on multiple devices.

Minecraft does not run on steam. Buy the game only through the official Minecraft site.

In fact, you don't pay for the game, but for your account. So you can log on to any PC.

You don't need steam for minecraft. If you want to play the java version, you have to install java beforehand (but you probably already have it installed).

You don't need steam. Simply download from the official website http://www.minecraft.net/...ecraft.net. You can then install and play this on all other computers using your minecraft.net account data

And then I don't need Java or why do the others write it

You need Java.

No, as far as I know, all necessary Java libraries are included as standard. You don't have to install extra Java for this.

So it is, Minecraft has a minimal Java Runtime with it. You only need a full-fledged JRE if you want to use mods or other additional software.

You don't need Steam. You just have to consider which edition you want - Java or Windows.

The Java Edition is generally better, but with Windows Edition you can also play with Pocket Edition players.

If you want to install Java Edition, you have to install Minecraft on minecraft.net/de-de and if Windows Edition, then you have to install Minecraft in the store, I think.