You may find some useful info here regarding free online learning
https://www.livelingua.com/project/fsi/Cantonese/.
Move your question to Society & Culture>Languages or Local Business>(location near you) as it's currently in Health>Diet & Fitness and not applicable to this subcategory (and thus decreases your chances of getting many useful answers).
You can move your question by clicking Edit (pencil icon for mobile)>Edit category just beneath your question, then selecting the category in which it is better suited.