So im using Ruby and jekyll to create a website but the ls command apparently doesnt exist what do i do?

ls is built into bash
if you’re not using bash, then what are you using? Perhaps you should be using bash instead, or perhaps you need to find out how to do the same action in that other shell.

I installed ruby and im using the start command prompt with ruby

So you’re on windows? I belive dir serves a similar purpose to ls
You could also use your regular file explorer

So either use windows’s tools, or get bash somehow (cygwin/git bash/WSL)