I need goods to unlock a technology. How do I get them?

There are several ways to obtain goods. You can produce them yourself by constructing goods buildings according to your requirements, or you can trade with other players for the goods you need. Goods can also be purchased with Diamonds. 

Hint: You should only produce boosted goods in your own city. Boosts for goods are given out as a reward for successfully acquired provinces, so you should keep an eye on those!