I'd download the 430 simulator. It's free and fantastic. You can get
proficient with just that and your PC. You definitely need to know the
Garmin logic.They sell BY FAR the most IFR GPS units.

http://www.garmin.com/products/gns430/

Also, try to get this person into actual conditions. Your own performance
will calm down and get down to business. I got my CFII long before I ever
became a CFIA, and believe the best instruction is from one who is calm and
enthusiastic. Don't worry about the little variations from perfection, just
get your student out in actual to build confidence. After that, fine
technique comes naturally.

Karl