The Coursera Deep Learning specialization is great. It starts with the basics, including a gentle introduction to the intuition behind the maths, then goes on to cover many important application areas. If you like a more structured approach (e.g. assignments, quizzes), then this is for you. It's quite a lot of work, but it will get you from completely clueless to comfortable with most of the concepts and ready to explore the field on your own.

I found the FastAI course too light on details and the Jupyter Notebook based deep learning framework they built abstracts too many details away ...and is yet another (not very popular / used in practice) framework to learn.