This is a manual adjustment. not stopping you very well, does damage to the drum.). Consider doing both sides(drivers and passengers at the same time).
Anyways, as you realize this is a lay under the car job.
You might be at the point at which it would be easier to inspect the whole darn thing.
You know, all this information is in a "repair you VW book" if you would go to a second hand store or the public library with pictures" Much easier. If it is drums all the way around then any old aircooled VW repair manual will do(of any year) because nothing much changed. Assembly is all the same. Beetle, van,Type 3. In many cases you can approach another beetle owner and ask them directly if they had ever done it. A young guy has more than likely done it.
You may be having more problems than unadjusted brake shoes...I am thinking air in the brake lines(meaning something is leaking brake fluid.) That is a concern. Because that means no brakes. And that comes without warning(well, you got some warning, like right now)If the pedal goes to the floor, it needs a mechanic if you are not one to inspect and repair it. That is, "if" you value your pretty face or your life.?