This achievement is unlocked during the 3rd level of the first Anglo-Saxons campaign, "Edward the Confessor"
I found the achievement to be fairly simple using the following method:
At the beginning of the level you will fight off attackers at the castle. They will have catapults, which you can take for yourself after you kill their crews (unsure if they can be destroyed or not, I used archers to kill the crews just to be safe). As soon as you get access to your base and get the objective to deliver catapults, begin recruiting slingers (they are the cheapest units) to take control of them, there should be five in total. Make sure to clear the area near the catapults, as there will be enemies there. Once you deliver the fifth one, the achievement will pop, provided you did so before nightfall (you will know when that is because new enemies will start attacking you). Additional catapults can be recruited after building the blacksmith, should you need them.