Look in any decent manual. There are photos or diagrams there showing position of distributor drive gear when no 1 cylinder is at TDC on firing stroke. Much easier to refer you to a manual than try and desribe it, or work out an electronic way of getting a diagram or picture onto this board without a scanner.
Note that the drive gear must be twisted a little anticlokwise before inserting into the camshaft gear. It will turn as it engages (make sure the oil pump shaft is in the right position for this); the picture relates to the position when the gear is fully engaged.
To check if the cam is in the right position for no 1 firing, the inlet valves for no 4 should be about to open, and the exhaust valve closing. (Both no 1 cylinder valves should be firmly closed with approx the correct rocker clearance!)

Section : Ignition and Distributers

Distibutor mechanical timing

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Distibutor mechanical timing