If you are wondering, how would you be able to go to the Nether, it's simple you just need to obtain 14 obsidian blocks and one flint and steel.
First put 4 blocks of obsidian and then place 4 blocks on top of the end blocks and then finally connect the top with 2 blocks.
The last thing you would need to do is use the flint and steel to strike and activate the portal.
The Nether gives you potion ingredients and other materials like gold and iron and other materials you can't find in the Overworld.