[mbed-tls] What is the right way to use ecp

I have a very basic use case, to use a buffer and perform ECDSA encryption in a TA application. I also want to read back the private key which is generated.

I see functions like mbedtls_ecp_gen_key but I have failed to find enough details on what steps to follow to use this function. It will be really helpful if I can be pointed to a example. Or let me know If there is some other way to achieve the end goal.