I am wondering the travel path of the engine oil when it is poured into the filler hole at the top. Where does it meander to first?
Engine injectors? oil cooler? oil filter? the pan has to be the last right?

From the Filler to the Sump Pan..
From Sump through Sump Oil Strainer to OIL Pump...
From Oil Pump to OIL Coolers...
From Oil Coolers to Oil Filter..
From Oil Filter to MOP (Metering Oil Pump) and Eccentric Shaft.
Through Centre of Rotors and back down to the SUMP again...

The Cycle starts again... :)

great! thanks!

When oil is poured into the filler hole, it drains straight down through the intermediate iron and into the oil pan. Right by the dipstick. Simple as that.

When the engine is in operation, it follows the general outline posted above.