so firstly i recommended that see my previous lecture about lambda calculus on my channel that make help you for more understanding to this topic.
lambda calculus introduction https://youtu.be/yb9-H4i1OMA
lambda Abstraction and Free/Bound Variable https://youtu.be/QQ0tdOzUf9A
Ppl Principle of Programming language Topic-substitution and Beta Conversion and also Include Alpha and Eta Conversation or Reduction .
