https://www.youtube.com/watch?v=QCif_-r8eK4 Intro, what is test driven development.
https://www.youtube.com/watch?v=B6xhmya6Mo8 Common questions/objections.
https://www.youtube.com/watch?v=HhwElTL-mdI View first 15 minutes before code appears.
Once these videos have been viewed. Start with Issue #1 practicing Test Driven Development and do issue 1, 2, etc. for one hour.
After doing this practice, change the above code to use a real unit test framework, as an example for embedded C development, use Unity - http://www.throwtheswitch.org/unity
Then for the real stuff on embedded C development, read on how to do this on the target and try it. https://github.com/andershedberg/testdrivengit/blob/master/Unity.pdf
Also see the book - https://pragprog.com/book/jgade/test-driven-development-for-embedded-c ( of which I was a reviewer before publishing ;-)