Of course, Underworld monsters will also be attacking you, but they may drop useful items, and you'll find plenty of healing potions in the pots you smash. You need to ensure you have room to dodge and no stray blocks to get caught on. Setting up this ash bridge can take some time, as you may need to break some of the Underworld structures in the process. I may have gone a bit overboard with this bridge - the point is you need plenty of room to run, because it takes some time to wear down 8,000 life with Pre-Hardmode weapons. If you're close to the eastern side, it will move slowly west, forcing you to stay ahead of it. It will then move the opposite direction. The edge of the map you are closest to is where the boss will spawn. As to where you should do this depends upon where you entered the Underworld. You should have plenty of ash if you've farmed Hellstone. The best thing you can do for yourself is to build a platform of Ash blocks (so Fireblossom can spawn) across a large area, just a bit above the lava. You can use platforms, but Ash will let Fireblossom spawn on it later, allowing you to harvest plentiful amounts of them later. If you don't already farm for potions, see my guides to Plants and how to make Potions. Regeneration and Ironskin Potions are recommended, as well as Well Fed. It is much easier to fight ranged, but broadswords can hit the wall of flesh even when you're running away from it because of their arc going over your character's head. Weapons of that level are also recommended - the type is up to you. Meteor Armor with the Space Gun is perfectly viable, so long as you have 300+ life. You should have at least the Meteor Armor or, preferably, the set you get from Crimson/Corruption bosses in order to kill the Wall of Flesh. This guide to defeating the boss will describe the battle, suggest the armor you should have to be safe, and recommend a good 'arena' setup for defeating it. Its defeat initiates Hard Mode in your world, where greater challenges await. The Wall of Flesh is the toughest challenge of normal mode in Terraria. Drops: Pwnhammer (100%), Clockwork Assault/Laser Rifle, Trophy/Mask, with Warrior, Sorcerer, Ranger, and Summoner Emblems

Wall of flesh terraria