Demo C/C++ program exploit through environment variable (Information Security Learning demo )

I'm looking for a freelance experienced tutor who could guide and teach through a virtual session how to exploit a small demo code written in C (a few lines) for a buffer overrun using GNU Debugger and pwntools for personal learning purpose. Please respond with the hourly rate and earliest availability. (Reference Example-1: https://ironhackers.es/en/tutoriales/introduccion-al-exploiting-parte-1-stack-0-2-protostar and Example-2: https://0xrick.github.io/binary-exploitation/bof1/). Reference examples are given for explanation.