Provide market space for families and distribute goods to your peasant populace.
The marketplace in Manor Lords is one of the game's trickier mechanics. You'll likely first encounter this building when you receive a message from one of your families asking for space to set up a market stall where they can distribute their goods. If you want your populace to have plenty of fuel and food early on, you should build one sharpish.
As you assign more families to chop wood, forage food, and produce items, you'll start to see more stalls appearing on the market providing their goods to your subjects, but it's unclear what the purpose of this actually is. It doesn't provide regional wealth in the same way trade does, so what's the point? Here I'll explain how Manor Lords' marketplace works, plus provide some tips for when setting up your own.
While the trading post is the best place to earn regional wealth in Manor Lords, the marketplace is where you distribute items to your population such as food, clothes, and most importantly, fuel. Access to lots of different goods boosts your town's approval, granting a higher rate of population growth. It'll also let you amass more treasury while maintaining a happy populace, since using the manor to tax your subjects reduces approval.
Providing access to fuel, food, and clothing are also prerequisites for upgrading your burgage plots—your villagers' houses—letting you build more advanced workshops in each, and gain extra regional wealth from them every month. A thriving town needs a bustling marketplace with lots of stalls and a variety of goods available.
Here's the basic rundown of how that works:
Generally the most important tip related to the marketplace is to staff your granary and storehouse with families, since this will provide lots of goods, and enough crossover that you won't risk blocking resource access if you reassign a stall family from a production building to do something else.
As mentioned above, there's no such thing as too many stalls; you want to provide all the stuff you're making and harvesting to your populace for high approval and its benefits. If you want to boost approval even further and you have lots of regional wealth, you could even import fancier foods and clothing at the trading post, which the family there will distribute via their stall.