While it's true that the orientation of the distributor doesn't really matter as long as the rotor is pointed at the terminal that has the spark plug wire leading to cylinder #1, when the #1 piston is near TDC, it helps to have a standard way of setting the distributor since there isn't enough room to plug in the ignition module in some orientations.
First, if you have a compression tester use it to determine when cylinder #1 is on it's compression stroke (pressure rising) by turning the engine over using the crank pulley nut (18mm, maybe 19mm). Turn it over in the direction such that the distributor rotor turns clockwise. Then continue turning the crank until the lines on the crank damper line up with the scale. If you don't have a compression tester, then get a friend to stick his finger on the #1 spark plug hole until he feels the pressure building and carry on the same way as above.
Next, stick the rotor on the distributor shaft and slide the assembly into the engine. There's lots of things that get in the way, and you may find that the only way to get it into the engine is by removing the module. Once it's in the hole, you don't have to pull it all the way out to adjust it by a few teeth one way or the other. Here's the trick, try getting it to engage the camshaft teeth so that once it's seated, the rotor is pointing towards the small vacuum port on the back side of the plenum (see pic). Once you've got it, note where the rotor is pointing using some reference on the engine (like the vacuum port) and slip on the distributor cap. Then rotate the distributor body until the post shown in the pic is lined up to your reference point, and tighten the distributor hold down bolt.
Again, by doing it this way, your ignition module ends up pointing in a direction that makes it easy to plug in the connectors. Don't forget to set the ignition timing as per Pyrthians instructions.
