Serve site from subdirectory

[CubeOfCheese]

Hello I am trying to serve this site from a subdirectory on netlify. siteurl.com/blog

I am having trouble achieving this on netlify so I decided to try to get it working locally first but I am having trouble with that as well.
I have set the baseUrl in site/config.toml like so
baseurl = "/blog"
But when I run npm run preview it opens the site at localhost:3000 instead of localhost:3000/blog while the latter url produces a 404 error.

Any assistance with this would be greatly appreciated and I am happy to provide any clarifying information

[martinjagodic]

Closing as this is not an issue but a request for help. @CubeOfCheese if you still seek an answer to this, please join us in Discord.