The posted notebook can be executed, but Raku have to be installed for that. The function StartRakuProcess takes the option setting Raku->"some/path/to/raku" that allows to specify where the Raku executable is. (To get Raku see https://raku.org or https://rakudo.org .)
StartRakuProcess
Raku->"some/path/to/raku"
After installing Raku the following packages have to be installed:
"Markdown to Mathematica converter (CLI and StackExchange examples)"
"Using Wolfram Engine in Raku sessions"
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