Mostly it's go through the normal ores until you have gold/platinum, which should summon the eye of chtuluh from your stats otherwise just force spawn it with the crafted item, kill to spawn Dryad which sells dusts to clear corruption/crimson, use that to get access to shadow orbs/crimson hearts(can instead use Dynamite which is sold by demolishioner or found in chests), break 3 to spawn eater/brain, kill to get components for new pickaxe+armor+weapon tier(shadow or crimonite), then go to hell(literally), get some obsidian or meteorite optionally, mine hellstone, make pickaxe/weapon/armor as needed, spawn Wall of Flesh by dropping guide voodoo doll(dropped in underworld) in lava, killing him spawn corruption/crimson and hallow and starts hard mode.
Destroy demon altars with Pwnhammer you got from Wall of Flesh to spawn hard mode ores in the world, explore the world again(or check map of areas already explored) and farm each tier. You need the pickaxe from the first tier to mine the 2nd tier, you need the Anvil and tier2 tools to get tier3 and you need the tier 3 forge to craft everything else. Once geared up in tier1-3 armor or Ice Armor(optional)+weapon, spawn bosses by farming the required materials or using any drop you might have found, kill the bosses. Each bosses drop Hallowed Ingots, make Drax or Hallowed Pickaxe(same items, just different noises). Killing any boss starts spawning Chlorophyte+Planterra bulb in underground jungle, go there, mine Chloro and craft Chloro armor/weapons, then spawn Planterra, kill it, drops the key to open Lizhard Temple for Golem and Dungeon now spawns hard mode mobs. No additional progression from there, just farming whatever, Halloween event too I guess haven't tried it.