Select the castle icon, then place the green flag anywhere on the map. Next to those squares you will see other icons, for now, all of those are irrelevant but one. This will bring up a palette of different colour squares.

Go to the terrain editor ('Tree') choose the 'Flag' icon. As there is only one player, you do not need to set any more territories. Next select 'Edit' (the red button in the bottom right) to bring up the map. Firstly set the starting goods for your map (this is the wood, stone, iron the player starts with at the beginning of the mission). Now, the next thing to do is to configure your missions (if you chose Kingmaker, then ignore the next steps). The two on the top allow you to choose between 'small' and 'large'.

In the mountain icon, there will be 3 small squares near the grid size selection. Once you see the map, click the big tree (the terrain editor). The way to do this is to click the red 'Edit Button' in the bottom right. This is something that they've hidden quite well in Stronghold 2. Once you've done this, you want to choose the map size. The first thing you should do before creating any map is decide what map you want to do. Finally, we have Peace Scenario's, peace scenario's are similar to war, except instead of being focused on armies and attacking, they focus more on reconstruction and helping other Lords or villages. Third, we have War Scenario, war scenario allows the player to create his own campaign of sort, setting invasions, available troop types and so on. Secondly, Free Build, this type of map allows the player to build a kingdom and an army for however long he wants without any form of enemy attacks (as of 1.4.1, there is an option to start invasions to test your kingdom's strength and to make the game more interesting). The first is Kingmaker (which is basically Stronghold 2's version of Skirmish, as seen in Crusader). It can be very difficult to use but at the same time it can be a joy to use! The map editor allows you to create 4 different types of maps. The first thing you should know about the Stronghold 2 map editor is that not everything is as clear as it may seem. Whether it's Kingmaker, Free Build, a War Scenario or a Peace Scenario! Plus, the guide has pictures! :D I hope these hints and tips help you out when creating your very own Stronghold 2 map. Now I'm sure others such as Lord_Vetka have made tutorials for this already, I have wanted to do this for a while, since the Stronghold 2 editor is my strongpoint.

Stronghold 3 map editor guide