Trading is an important part of any thriving civilization. Age of Empires IV gives you the chance to establish trade routes with trading posts across the map. Using trade helps to increase the number of resources being brought in by your villagers and is important if you want to build better units and advance your current age.
Your first task in establishing an effective trade route is to locate the trading posts on the map. If you are using the French, the Trade Posts will automatically be marked on your map. There will always be a few Trade Posts on the map and if you start off in a random location, you will most likely start near one.
Trade Posts can only be used by specific units. To get these units, you will need to progress to Age II. Once you reach the second age, you will be able to build a Market. Markets are used for trading your resources for other resources. They can also be used to create Traders.
Once you have a Trader created. Lead them to a Trade Post and interact with it. They will automatically set up a trading route and bring gold back to your civilization. If you are playing as the French, you can change the resource that the Trader will bring back. Create more Traders to get a steady flow of gold or other resources back to your base.