Look around the map if you feel like it though. When I get bored making this, I put random stuff in it that might help you. I recommend multiplayer in this map, as it does get fairly difficult, and you would get through it faster.
Creating a Nether portal is actually against the rules, because the Nether is in the normal world. You can find nether islands to the west of every other island. For example, the second island has a nether island to the west of it, then the 4th island has one, and the 6th island has one.
The End is currently pretty big. There's a huge square as big as the normal ones in it, but it's made of End Stone. It also has obsidian pillars on it with chests in it. Just make sure you kill the enderdragon when it's above some blocks, or you'll miss all the experience orbs.
Need help installing? Read our map installation guide.
This map was made in Minecraft 1.4.7, to avoid any possible bugs while playing, it's best to play on the same client version. You can change it in the "Profile Editor" of the Minecraft Launcher.