Berlingo 1.6 petrol timing belt

[Leadbasher]

Hi all and thanks for accepting me to this site. I hope I may be of assistance in the future (I am a qualified panel beater and sprayer).
However, as to now; I have recently bought an old berlingo 1.6 petrol multispace (2001). It's an NFU code engine.
I was a bit short of funds so decided to have a go doing the timing belt myself.
I locked the cam sprockets but not the crank as I couldn't find the hole. I can't imagine it moved though as I retightened spark plugs.
Fitted the belt with marks aligned with sprocket notched. Fitted belt. Turned it over manually untensioned but when I tensioned it it seemed very hard to turn over. Marks had also gone off by two notches. I fear I may have now damaged the top end as it runs real rough and cuts out. Don't know what to do to reset crank and cams and try again. Any advice greatly thanked.