How to set IC OR CI Engine timing without any gear wheels marking If open head cover only?

First loosen the time belt by pushing the idler, then remove the spark plug for cylinder No1 put plastic rod inside the cylinder length enough to come out the cylinder head when the piston at BDC ( so you can catch it not to fall inside the cylinder )rotate the crankshaft pulley untill the rod come out up completely and when start to go down stop and then rotate the camshaft pulley until the corresponding c