For this blueprint you will need to complete the "Threading the Thracian Needle" quest, which tasks you with escorting a caravan to an abandoned Town Center. Some main things to keep in mind are that you should keep a relatively slow and steady pace, it's not a rush level and can only kill you in the end, and if you need to stop to allow your units to heal up a bit, do it. Be sure to convert as many of your enemies as possible to bolster your ranks as you trek across the map, which means you need to keep your Augurs and Druids alive, although they also heal you so it's even more beneficial to keep them alive. Whenever you get the chance to sneak around a group of enemies, take it, because the best way to avoid losing units is to avoid combat as a whole. Don't allow your units to get spread out, and always make sure your caravan is close to your military units.