This is a good introduction focused on tensorflow. https://www.youtube.com/watch?v=vq2nnJ4g6N0 (Tensorflow and deep learning - without a PhD by Martin Görner)

The ML/DNN rabbit-hole goes deep. If the video above leaves you wanting more, http://www.deeplearningbook.org/ does a good job on drilling into more specifics for the various techniques used. The examples on the tensorflow webpage are also very good.