The first link gives me 404, seems like they are now a fourth part series:
https://sachachua.com/blog/2014/06/read-lisp-tweak-emacs-beginner-14-try-emacs-lisp/
https://sachachua.com/blog/2014/06/read-lisp-tweak-emacs-beginner-24-understand-emacs-lisp-code/
https://sachachua.com/blog/2014/06/read-lisp-tweak-emacs-beginner-34-can-make-things-convenient/
https://sachachua.com/blog/2014/06/read-lisp-tweak-emacs-beginner-44-can-add-features-deal-errors/
I find
consult-ripgrepto be excellent for this.