You will be surprise what you can learn from YouTube. There are great how-to videos from DIY alarm companies. Link 1 Link 2
Honestly, the best thing you can do for this technician is get him a volt meter and teach him how to use it then and enroll him in a community college intro to electronics class. If he had a volt meter and knew how to work it, that REX button should have been easy to figure out. Is there a community college that offers an intro to electronics course? You can tell a tech all day what a NO/NC circuit is and the difference between a supervised and unsupervised circuit, and resistance values, but without him knowing why these things matter he will never be of much use. Can you pair him with a knowledgeable tech who understands these things, preferably one who is sloppy on install the two will teach each other their strengths and both become independent.
Just a thought from computer guy who struggled with these things, who was paired with a pinball tech to install highly complex access control systems.
Basic electronic and electricity classes are the best way to start, augmented by instruction on meter and toner usage and On the Job Training...One of the ways to demystify it is to use a door bell analogy and reinforce that it is all nothing but dials lights plugs and switches...
Try this: http://www.nationaltrainingcenter.net/index.xml
Their bookstore has the NTC Purple Book, which is for Access Control. Blue book is for alarms/low voltage.