You need nodejs installed
To install the downloader simply run npm i -g https://github.com/Mohd-PH/sm3na-mp3-downloader
To use the downloader first you need to get singer's ID from sm3na.com
For example if we want Sayed Darwish songs, we would go to his page https://www.sm3na.com/audios/126f152ed3 as you can see the id is 126f152ed3 then go to your desired downloading folder and run the command sm3na 126f152ed3 then wait for it to download the songs