Cam Chain Replace

hi all,
I'm replacing my cam chain. My shop manual says "Rotate the crankshaft so the timing mark is at the top and journals are at TDC...".

So, I can see the timing mark. But, my motor is together and the cylinders are on- so how can I tell if the journals are at TDC?

Thanks

Pull a spark plug, shine a light and watch as the piston approaches TDC. You can also use a stiff plastic soda straw to tag and follow the piston movement near TDC. Just don't stick anything into the spark plug hole that can 1.) fall in or 2.) that is hard and stiff enough to jam things up in there.

Thank you