The Thom book 4 should give all the information you will need to help the guy, it does have both methods for the whizwheel in it so it could be confusing. I taught myself wind up for the nav exam but when I came to do nav for real my instructor taught me wind down which is now my prefered method. A good understanding of the map including how to plot points, how to fill in a nav plog, good understanding of the whizz wheel and radio navigation basic theory should get him through.