How to Get to the Netherworld in Minecraft

Fill your Iron Bucket with water. You can fill your bucket at any of the lakes or oceans on the surface, or you may find an underwater grotto while you're digging. It doesn't matter where you get the water; just make sure that your bucket is full.

Find a pool of lava. This can be difficult, as lava is usually buried deep underground. You may get lucky and find some lava on the surface, but most lava is found after you dig. The location of lava is random, so keep digging downward until you discover some. Lava is very dangerous, so be careful around it.

Pour the water over the lava you find to create Obsidian. The water will cool the lava and transform it into Obsidian rock. Obsidian is harmless, so don't be afraid to touch it.

Harvest 10 blocks of Obsidian with a Diamond Pickaxe. Obsidian can only be harvested with this tool -- using a lesser-quality pickaxe will destroy the Obsidian. Lava sources vary in size, so you may need to find more lava if you can't harvest 10 Obsidian blocks from one pool.

Create a Nether gateway with the Obsidian blocks. A Nether gateway must be a specific shape in order to work. Arrange your rectangular gateway with two blocks on the bottom, two columns of three blocks on each side and two blocks at the top.

Equip the Flint and Tinder tool and use it on the Nether gateway. This will activate the purple Nether portal that will transport you into the Nether. The portal may not activate on the first try -- just keep trying with the Flint and Tinder until it activates.