Merchants can be trained at a Town or City with at least a Market building present This scales with the overall level of the Merchant, which is boosted by either surviving a rival Merchant's buyout or by successfully outpricing another faction's Merchant on a nearby resource. Leave your merchant next to the Resource node and they will generate a small amount of income per turn. You train them (you need a Market building in your City or Town) and send them out into the world to look for Resource nodes, marked on the map with a little image of a pile of wood, a pot of wine, or whatever resource is common in that region.
Merchants are very simple and work much like they did in Medieval 2: Total War ( one of our favorite Medieval strategy games of all time).
