In the "Field of valour" scenario, i do not understand the special rule:

"If an enemy unit is destroyed by wounds inflicted as the result of a retreat", the Daqan player... gain 1 VP.

So, i must wound and make retrait the enemy unit to gain the VP?

When a unit retreats and it's pushed off the mapìs edge or against another enemy unit or an impassable hex (water, for instance), that unit receives one wound / hex it cannot retreat. If you're able to eliminate a unite in this way, you score 1 extra VP.

Hope this helps