scenarios are premade games. here is what i am talking about:
<?xml version="1.0" standalone="yes" ?>
<scenario>
<players>
<player control="human" faction="tech" team="1"/>
<player control="cpu" faction="magic" team="2"/>
<player control="closed"/>
<player control="closed"/>
</players>
<map value="one_on_one"/>
<tileset value="forest"/>
<tech-tree value="magitech"/>
</scenario>
i will tell you what does it means: firstly, the scenario, is based everything on this file. in the players, you can give players to each slot, faction, and their team. the map value is the map... tileset is the forest, winter_forest (and maybe jungle?). the techtree is the magitech, this consist the tech, and magic faction. at last you have to close the scenario file.