Finally there's a way to add custom teleports and redstone activated commands to the game. However, while it may look simple, often it's not. In this series, you'll be able to learn all about how command blocks work - from the very basics to the insanely hard stuff.
What exactly are they?
Command blocks, in a nutshell, are a block that when powered by redstone, uses the command inputted into it. They're designed for adventure maps, but they could be used in a normal map if you really wanted to use them.
How do I get one?
Annoyingly, you can't get them from the creative inventory. Instead, you have to enable cheats (if cheats are disabled on your world by default, then open the world to LAN and change the setting there) and use the command /give [name] 137. This will give you 1 command block. If you need more, you can use /give [name] 137 [amount].
Setting them up
You can only edit the command a command block outputs when you're in creative mode, so if you're in survival or adventure mode, use the command /gamemode 1. Then, right click the command block and a box to type in a command will appear. You don't need type in the / - you just need to type in the actual words in the command.
In future tutorials, I'll be explaining how to choose who'll be affected by the command, what commands you can use and how to make multiple commands fire off at once.