bottom dead center rd28 help apprectiated.

hey guys! can u tell me how i can tell im at bottom dead center on my rd28?

i have all my markers ligned up for the timing belt but i realise the crankshaft is doing two(?) revolutions per cam shaft rotation.

how do i tell im at bottom dead center on an *expansions stroke

*is expansion stroke as its pulling fuel into the cylinder?

probably not something i should be doing on my own but im taking my time to get it right... :D

i have the rocker cover off and can see the cam and lifters.

all good got er started :D

4 stroke, remember this.: suck, squeeze, bang, blow, -- intake,compression, explosion, exhaust..