how do i know when the #1 cylinder is at TDC. the timing belt snapped and it threw the timing off. Thanks!

align crank with timing mark on block same for cam

why would my h23 have no compression on three cylinders and 150 on one of them checked the timming its all correct ?

Could be head gasget. Piston could be burned. Valves Could be messed up. A number of things.