Resources for Training Memebers

We have a member on our team who has been on the team for about a year now and has functioned as our scout. He isn’t super engineering minded, but he wants to learn how to build robots. We have tried training him with having him duplicate our robot, disassembling mechanisms, explaining our design process, and trying to get him to design simple mechanisms.
None of this is working. Is there any other ways to teach him and is there any online resources that could help him learn?

This guy’s videos could help: