A lot of people here recommend fast.ai which is solid, but not really that useful if you want to do research. I would start with math foundations: basic linear

A lot of people here recommend fast.ai which is solid, but not really that useful if you want to do research. I would start with math foundations: basic linear algebra, stats, probability and some analysis. CS undergrad level is plenty of math for start. Then I would try to understand back prop on intimate level: learn how to calculate gradients, maybe take a look on how autograd works as well. Then you should know a bit to pick your next steps by yourself.