@Koalaknightmi its probably becuase u haven't successfully installed express. Try to either change the folder name. It may because of a space, as I have been annoyed by such. Please vote if this helps!
I totally understand your confusion. Me and @CaptainPoultry are very bad at nodejs and needed a way to make the navbar in less code. I also thought it would be cool to use it, as I just learned it. @AdCharity