I saw on youtube that the wither is hard to beat, so I thought I would attempt to kill one to prove I'm better than it. After searching "Wither", it only came up with a wither skeleton. How do I spawn the wither, and how to I make the spawner?
To spawn a Wither you need to build it like with Golems (Snow and Iron), you need 4 Soul Sand in a T Shape and 3 Wither Skeleton Heads on top of the top 3 Soul Sand Blocks More Info here, when it's made it'll cause an explosion and the fight is on
As Memor-X said, you can spawn a Wither with 4 Soul Sand and 3 Wither Skeleton Heads.
However, if you desire to spawn the wither by "unlegit" means you can use the command:
This instantly spawns a Wither Boss in front of you.
Obviously you have to have commands enabled to use this command.