I tried a DIY timing chain kit on my 4.6L 2v 2001 F150, and when I went to start it...nothing. I think the engine is seized, really hard to hand turn the crankshaft, even without the belt on....Advice??

 

Pull it back apart and see what you did wrong?
I have seen a bit of everything over the years
Chains not going around all the pulleys correctly or a mispositioned guide locking things up is my guess
Hopefully, the valves are not bent from being mistimed or the chain jumping
Tear down and inspect
We've all done it