What are all the activation codes that you can use?

How does the war horn give out gold I don't understand how its connects to gold?

The war horn will reward an amount of gold. The minimum is 500, but sometimes you get more. You can double it with bonuses and watching adverts.
Wen you claim the reward it is added to your gold stock in the inventory / items. This is not the store in the warehouse totals at the top of the screen but it is in reward chests that you can see in your items bag and can be opened to use when needed.