About the same thing olddog said and expanded some (probably more than you want or need).
Rotate the crankshaft (CW as viewed from the front) until #1 cyl is TDC on the compression stroke (make sure it is not TC on the exhaust stroke).
The factory distributor attitude is with the rotor pointing near 3 o'clock to fire #1. When the engine is running the rotor will be turning CW.
Looking down on the distributor:
Stab the distributor with the rotor in place. The dist drive gears are helical, as the gears mesh the rotor will turn CCW so start the stab with the rotor pointing somewhere after 4 o'clock and when in full mesh the rotor will end up pointing near 3 o'clock when the distributor is seated.
When you get the rotor in that position tighten the hold down bolt. Loosen the clamp screw and turn the dist head until the breaker actuator is on the top of the cam lobe, set the points @ .020" with a feeler gage. Turn the dist head CW until the points are closed now turn the head back CCW until the points just start to open and tighten the clamp screw.
The engine firing order is 1342 and the rotation of the rotor is CW so when you put the cap on, put the #1 cyl wire in the tower that is near 3 o'clock, #3 wire near 6, #4 wire near 9, and #2 near 12. That is good enough to start the engine and tweak the timing in to TDC with a timing light.
The TDC timing mark is just a line scribed on the flywheel sometimes marked with “0”. If you are using an induction timing light and cannot find the timing mark engine running at idle rpm and turning the distributor head, put the timing light pick-up on the coil wire. That will provide 4 times the light flashes to light up the timing hole. You can time the engine with the induction pick-up on either #1 or #4 or the coil wire, it is all the same timing.