Minecraft wiki entry for Multiplayer_PvP_bases, associated text: First of all, you're going to need a way into the nether. Get enough obsidian/molding supplies to make a portal, then make and hide one (generally underground). Be sure to claim this chunk! Then /f sethome next to it, and head on through. If it's a good enough place for you, keep going. If you're in a bad place (i.e. over a lava lake), then you should probably head back to the overworld and move your portal elsewhere. From here, there are three ways to go about your base (keep in mind that all the defenses in the world won't save you if your portal is in your base).