I'm willing to learn AI from scratch and I like to become an AI developer, I need a roadmap from scratch to excel in Ai

Thank you for look , I need an clarification because I chosen math/computer science in my 12 th grade , after I have done my UG in chemistry, now I'm pursuing PG in artificial intelligence and data science, I'm left with 3 years gap in Computer science, so I need to co-up with some basic and foundational technology to meet the eligibility criteria for the base of IT , what should I do ? Suggest me some valuable insights