How do you adjust timing on 1971 super beetle?

First, you need a timing light. Loosen the nut at the base of the distributor just enough so that it can be rotated. With the engine running at idle, point the light at the top of the rotating main pulley. They'll be some marks (notches) that comes up on top-dead-center (when the light flashes). You rotate the distributor until the proper mark is in the correct position, in relation to the split in the engine case as your reference. However, that's the trick, you have to look up you model and/or engine code(if it's been replaced) and cross reference the proper timing for your particular engine. The "How to keep your Volkswagen Alive" by John Muir is an Excellent source for this issue and many other repairs. Once you've got it where it should be, tighten the distributor nut, remove your light and take it for a drive. Good luck. Set the valves first. Valve adjustments can affect timing.