In case I put you off by referencing BlueIris, do take a look at the SenseAI introduction as it has far more general application and will kick-start your machine learning experience.
https://www.codeproject.com/Articles/5322557/CodeProject-SenseAI-Server-AI-the-easy-way
Out of the box, the toy application will:
Detect objects in images
Detect faces in images
Detect the type of scene represented in an image
Recognize faces that have been registered with the service
More capabilities are planned for this FOSS software that runs completely on your PC (no cloud requirements)