In search of the Rune Sphere.

Good afternoon.
I downloaded the map because I really liked the first one; it's a great battle between humans and dwarves. And I encountered a problem: I'm reading reviews, and everyone seems to be completing it without much difficulty. What's the secret? I started on Veteran difficulty, Vittorio emerged from the dungeon, and a chaotic battle began on the surface. I have very few troops (there were no losses in the dungeon), and while the dwarves didn't have titans yet, it was manageable; the crazy griffins landed randomly, but far enough from the enemies, and the ballista fire was effective. But when the titans appeared, the question became: how do I kill them? If I don't manage to capture the tent, does that mean I have to restart?