13. Screencast + Text: How Does K-Means Work?
14 How Does KMeans Work V1
How Does K-Means Work?
The blog by Naftali Harris is spectacular at showing you how k-means works for a number of situations. You can try it yourself!
As an exercise for yourself, you might try coding up the algorithm yourself in Python. This blog by Mubaris Hassan may be helpful if you decide to take on this task!