Once again this one is very easy. You need to collect a currency called weapon steel. There's two different types of steel, Weapon steel is the red one. You can get weapon steel a couple of different ways. You'll get it mainly from killing enemies and breaking crates and pots around islands. you can also get it by refining red ore at the father ship later in the game. You will get the other kind while flying your ship. Should be pretty easy to get as 1,000 isn't a lot. You should get this pretty naturally. You use weapon steel to upgrade your weapons, pretty straight forward.