Trading is an essential Mount and Blade II: Bannerlord process. It's standard practice where you can visit one city, buy a good chunk of its perishable goods, and then sell it for a higher price in another city. This is a great skill that your character must have in the game. It is also important to note that you can increase your character's trading skills by creating trailers and having them travel the world on your behalf.
You won't be able to buy a trailer until later in the game. Create a cost somewhere close to 15 denar, which is expensive. They are similar to workshops, however, where when you create one they will continually make money for you in a timely manner. They're worth the time because they can freely make money without too much input, and it's more of a hands-off mentality. Not only do you need 000 denars for a trailer, these trailers require 15 guards. You have to give up that amount to make sure they're good when you send them out to the world.
To gain access to the Caravans, you must speak to a merchant in one of the towns after showing up. During the introductory process, you need to choose the chat option for “Set up a caravan in this town”, and you should be able to do so, given that you have all the requirements set and ready to go. Unfortunately, it takes several jobs in the game to make a profit, so you can expect to see losses when you start them for the first time, but if you have ways of making money fairly quickly, like standard trading, the quests or looting, you 'I'm fine.
Make sure to visit towns frequently to purchase lucrative items that neighboring towns could purchase for a much higher profit. After purchasing a caravan, this is a great way to ensure that your profits remain positive.
