You need to find TDC first, then the timing mark.
Use the right-hand hole to align the rotor.
The stator should be centred in the slots.
Fit the rotor lightly, so that it can be turned to align with the hole at the 38 BTDC mark.
The stator should only be moved a little when strobing, to advance or retard the timing if required.
This is for a Sparx unit, but its a similar procedure: