Have them review the last several projects completed from the install perspective. What went well, what didn't, what products and design decisions made life difficult.

Ask for this as a formal report, not just a list of notes. Developing and practicing formal communication skills and an analytical process will benefit both you and the employees in the future.

Anything IT related is probably a good focus as well. A managed switch, sonos and IP camera are relatively affordable for a test-stack, identify your common system requirements and have them configure from ground up.