>>1
Install MIT/GNU Scheme (or Chicken Scheme) and read either one of these:
* https://ds26gte.github.io/tyscheme/
* https://scheme.com/tspl4/
You can use GNU Emacs and Geiser to get a good development environment for various implementations of Scheme. Also, some people recommend Little Schemer and its sequel The Seasoned Schemer (Both are good books, too).
If you want to learn Common Lisp instead, I recommend Practical Lisp (https://gigamonkeys.com/book/) Read The Common Lisp Cookbook after that (https://lispcookbook.github.io/cl-cookbook/). Install SBCL (or CCL or Clisp) and GNU Emacs + SLY to get a good development environment (you can use Guix or Quicklisp as your package manager).
If you can't decide whether you want to learn Scheme or Common Lisp, you can just toss a coin or something. The choice doesn't matter that much because both of them are good languages.