1992 Nissan Maxima wont start

I put a water pump n a timing kit on this car. It was running perfect before but I figured I would do the timing belt while it was open. The car just turns over with no compression at the cylinders. Some people say the valves are bent while others say I probably didnt time it on the correct stroke. What do you think. I used a repair manual from autozone as a referral tool.