What Neilwood and Tursiops said are spot on. If she has never used a compass before, trying to learn how to use one underwater with all the other things that are going on, is foolish at best. That is a skill that can, and should be, perfected on land before trying to use one under water. It is much easier to visualize the "plan" and practice orienting when you are not trying to maintain buoyancy, etc., and if you mess up the plan, you can just walk back to your start point, analyze and discuss what went wrong and start over. Using a compass is not hard, but it does require a very good understanding of the basics, and then repetitive practice until geting around a course becomes second nature.