Hey @Jack_Woehr! You can find this and more info about how to work with Compass monorepo locally in the contributing doc that is part of the source on GitHub.
Running Compass locally in dev mode and building it for distribution is not the same. The most basic way of building Compass locally is to run npm run package-compass from the root of the monorepo. There are additional parameters that can be passed through the environmental variables during the build that are documented in the “Building Compass Locally” section of the doc.
We don’t really see many people trying to build it locally and as developers who work on Compass day to day we don’t set up our working environments from scratch every day so you might run into some issues while following the instructions there so please feel free to try this command and tell us if everything works well for you and we can try to assist if it doesn’t (although I think if you are able to run the app locally already, it all should go smoothly)