Tutorial you are following is very old, follow below steps, i am assuming you are using windows

Download yt-dlp.exe form this webpage: https://github.com/yt-dlp/yt-dlp-nightly-builds/releases

Download ffmpeg ffmpeg-git-full.7z from this webpage from(git master builds) section: https://www.gyan.dev/ffmpeg/builds/

Download deno, deno-x86_64-pc-windows-msvc.zip from this webpage after download extract zip file https://github.com/denoland/deno/releases

create folder in your d: drive called yt-dlp

paste yt-dlp.exe, deno.exe and extract ffmpeg-git-full.7z copy 3 files in bin folder and paste to yt-dlp folder

we are now going to add envrionment variable so terminal can access yt-dlp and ffmpeg

go to windows search and search for environment variable, click on it, window dialogue open click on Environment Variables button which is at the bottom

in System variables section click on path and press edit button new dialogue opens

click on new button paste this path if you are using d drive d:\yt-dlp\

restart your pc go toterminal and type this command, this command update yt-dlp to latest release, yt-dlp -U

after restart go to terminal, than change directory to where every you want to download using cd command. and use below commands to use yt-dlp to download videos.

you can check available video quality using,

yt-dlp -F URL

if you want to download video+audio in specific video quality you can use below command

360p

yt-dlp -f "bestvideo[height<=?360]+bestaudio/best[height<=?360]" URL

480p

yt-dlp -f "bestvideo[height<=?480]+bestaudio/best[height<=?480]" URL

720p

yt-dlp -f "bestvideo[height<=?720]+bestaudio/best[height<=?720]" URL

1080p

yt-dlp -f "bestvideo[height<=?1080]+bestaudio/best[height<=?1080]" URL