From where to start learning about sympy?

[Somiparno Chattopadhyay]

Hi! My name is Somiparno Chattopadhyay, currently in the final year of placement in MAKAUT, WB, India and awaiting placement. I'd like to ask what are the resources for beginners to understand SymPy code and where should I start from? I'd like to make a project on a CAS from scratch but inspired by your code, (and also contribute to SymPy) so I'd be very obliged to know the resources for starting out.

Thank you!