From this site, www.ausport.gov.au you can access free online courses developed by the Australian Sports Commission and the Australian Institute of Sport.
All it takes is to ENROL for free and then do a course. Start with the “Beginning Coaching General Principles” course first, it is most educational and free. It doesn’t get much better than that.
If you know of other coaching or sporting links, feel free (walnut) to add them to the list here.