1) Set the points gap. It should be 15 thou at maximum.
2) Remove all spark plugs and leads. Put your thumb firmly over No 1 cylinder (the front one)
3) Using the starting handle (car in neutral!) turn the engine until you fell pressure building up under your thumb.
4) Look under the front of the car and find the timing marks. Continue turning the engine until the mark on the crankshaft pulley is mid-way between the 5 and 0 degree marks. This will be good enough for now.
5) Get the vernier on the vacuum advance in the centre of the scale - this will make adjustment easier later.
6) Now move the distributor so that the points are just opening. You can actually use your flash timing light for this - connect it to the HT terminal on the coil, then with the ignition on, it will flash as the points start to open.
7) Secure the distributor in place.

Note where the rotor arm is pointing. Fit the No1 plug lead to the corresponding terminal on the distributor cap. Now fit the remaining leads. Anti-clockwise: 3,4,2.
9) Now you can test run and confirm that timing is pretty close. When you've done all of that we can discuss final tweaks.
Good luck, it get's easier the more you do it.