We recommend reading CATAN's website regarding expanded rules on the different scenarios. I've linked directly to the dev blog parts that do not contain story, but rules:
Scenario #1 - https://www.catan.com/news/2020-06-24/catan-legend-conquerors-developer-blog-series-part-4
Scenario #2 - https://www.catan.com/news/2020-06-30/catan-legend-conquerors-developer-blog-series-part-8
Scenario #2, Specific to cavalry - https://www.catan.com/news/2020-06-30/catan-legend-conquerors-developer-blog-series-part-9
Scenario #3 - https://www.catan.com/news/2020-08-03/catan-legend-conquerors-developer-blog-series-part-14
Scenario #3, Specific to forts - https://www.catan.com/news/2020-08-03/catan-legend-conquerors-developer-blog-series-part-15
These should be good blogs to get more information on the various rules in the scenarios.