How do I further progress? [duplicate]

After you get shadow armor, you need to dig down to the Underworld, and harvest some Hellstone, but be careful as it drops lava when you mine it, and it's very dangerous in the Underworld as it's full of lava and monsters. :) EDIT: Just to clarify, the Underworld is the deepest layer, and it will take some time to mine to, or you can follow some caves down to it. I recommend to bring some Obsidian Skin potions. I believe they're crafted from Fireblossom, Obsidian, and a Water Bottle at an Alchemy Station. They will help you stay safe from the lava and prevent you from getting hurt by the Hellstone, it burns you even if you just step on it so you should stay to the ash. Btw, you will need Hellstone to craft Molten armor and the tool set. It won't be easy acquiring the needed Hellstone, and you will need a Hellforge which is found in the towers that generate in the Underworld to craft the Hellstone Bars which are then used to make the armor and tools at an anvil. It's the final tier of armor and tools before hardmode.