Your world can be blessed with 2 sets of ores , which sound and look different , but fullfill the same purpose. Same thing with the corruption and the crimson.
If you still want the ores , go fishing. They will eventually drop.
To progress you need to fight the twins in order to able to fight against Plantera in the jungle biome. To spawn plantera simply destroy one of the small pink bulbs.
After defeating Plantera you may open the chests in the dungeon using their specific key. (Corrupted chest e.g.)
If you drop a Temple key , you will have to find the Temple in the jungle biome.
After you defeated the Golem in the temple , the Lunatic cultist spawns at the Dungeon. If you manage to take him down , he will trigger the Lunar event.
The Lunar event is the final stage of Terraria.
More things to progress :
- Trigger a Solar Eclipse
- Trigger a Martian invasion (very hard)
- Trigger the Lunar event (very very hard , will trigger final boss afterwards)
- After beating the Lunar event , enter expert mode and do everything all over againg for more drops.