The tutorial by Ingvar Stepanyan delves into Rust's macro system, specifically focusing on implementing a macro that evaluates Reverse Polish Notation (RPN) at compile-time. Despite the challenges faced in understanding macros through standard resources, Stepanyan shares a recursive approach to handle RPN, a notation using a stack where operands are pushed and operators pop the last two operands for evaluation. The tutorial explains the process of creating a macro that converts RPN into infix notation that Rust understands, detailing the steps to manage token matching, stack manipulation, and operator handling. It emphasizes handling errors gracefully by providing meaningful compile-time error messages for incorrect expressions, leveraging Rust's compile_error! macro and trace_macros feature. Stepanyan concludes by encouraging feedback and suggestions for further topics on Twitter.