You'll need to pull the head. turn the cam until it is at the TDC position (no.1 valves both fully closed and the distributor rotor pointing to the no.1 tower). Then rotate the engine to TDC (piston no.1 at the top of its rotation and the timing mark on the balance aligned with the reference indicator).

But again, as mentioned above, unless you got incredibly lucky, it would be hard to imagine that you haven't at least bent some valves if not marred some pistons as well. Even turning it by hand while its out of time you can bend valves enough to spoil the seating. Though I suppose you usually would, you don't necessarily have to hear or feel anything when it happens either.

I could be way off on this, but, one thing I find strange is that the chain was still draped around the cam gear. I would think that if the chain broke while the engine was turning, it would all end up down around the crank gear and get bound up perhaps causing some other damage. Unless maybe it broke in two spots? and part of it fell down while the other part stayed hanging over the cam gear (which would immediately stop turning). I'd make sure the old chain is the same length as the new one, if it's shorter, you may have some old chain still down in the lower cover or maybe in the oil pan.