Timing chain replacement

I am working on 2002 Nissan pickup
with 2.4 liter motor timing chains where
removed by someone else I'm trying to
get the timing right i brought crank to
tdc 1 cylinder compression stroke but
the cam timing marks wouldn't line up i
lossened the cams and turned them so
that the marks all lined up retightened
the cam bolts but now motor will not
turn at all what did i do wrong por how
do i go about getting it in time