If the starter runs, (the motor may not turn over, since the gear is not activated by this technique) the problem is the solenoid. The book tells how to secure the car, key off, out of gear, wheel blocked, find under the car the starter and solenoid, and short across the two solenoid leads with a screwdriver. This book was intended for the Sedan (old bug), Ghia, and Transporter (correct name for bus, I think.) It cost me $5.50 in 197?, but if you have to pay ten times that today, grab it.
Try e-bay or Amazon, or any place that sells used books.
A MANUAL OF STEP BY STEP PROCEDURES FOR THE COMPLEAT IDIOT, by John Muir.