What helped me when I started 4 years ago was taking some certification exams offered by AWS and Azure. They're a bit pricey in my opinion but I needed a structured curriculum to guide my learning.

Other than taking these exams, I just set up an AWS account and played around with the services, which is free if you stay within the usage limits of the free tier. I started with learning about the core services, how to provision infra using infrastructure-as-code, how the billing model works, etc.