The first part of the series. I got some prisoners, and people say they can be sold to inn-keepers, but there is not such option. Only to buy wine to all men and nothing else.

There are a handful of travelling ransom brokers that can be found in inns, sell to those. There is a mod that makes inn keepers buy prisoners as well. Lords and kings cannot be sold in this way; you will have to wait for a ransom offer for those but then, they sell for a lot more, the kings for over 10,000 sometimes.

There is a manual hidden away somewhere but I do not know how accurate it is.

Thanks. I've already figured it out.