Learn MbedTLS for Crypto

Hello everyone, first allow me to apologize for my poor English level. Currently I am assigned the task of learning about MbedTLS for Ctypto. After reading the document as well as the source code on github, I still don’t really understand anymore. This is the first time I’ve worked with such a large source code. So I hope everyone can give me advice and show me a step-by-step roadmap to learn and code about it. Thank you very much.