I may ask them to use a unit from the big box store or hardware to hang in several locations.
Have them do it and after 3 to 4 days mail them in to get the results back by email.
If you haven’t taken any education on how to do it, leave it to them and study up for the next ones. You may decide to purchase a CRM.
If you’re testing for a friend, use two carbon pouches. You probably don’t have issues with tampering. Make sure you have closed house conditions for 12 hours prior to start of test, plus for duration of test. Know where to place them; basement, main floor with crawl space, slab, two tests required for multiple foundation types…
CRM’s like the Air Things Pro and many others need annual calibration. Homeowner devices are just that, not for professional use. They can give you unreliable readings if not recently calibrated, plus what do you know about the one for sale???
And, what Larry says above…would you do a home inspection for a friend before you had any home inspection training? Radon training is the same when offering the public a service for a fee.