Please take my answer with a grain of salt, as I have always used/seen people use repl.it for this tasks, as it’s easier to submit a live solution.
However seems that the starting repo is a fully working express server, meaning that you would be able to:
1 - deploy it somewhere so it’s live on the internet.
2- run it locally, and make it accessible via tunnelling.
I think option 2 is “easier”, but it all comes down to your familiarity with node and the terminal.
With node installed on your machine you can simply run npm run start and you’ll have a running server working locally.
Then using something like ngrok or an alternative you tunnel your local server and submit that url.
Again this is just my possible theory, let’s wait and hope that someone offers a easier solution for you to work with.
I prefer to develop locally and not use the replit. To submit my challenge I deployed my github repo to heroku so I have a running application and use that url as my solution link and the GitHub repo url as the GitHub link. The pros for this is that your app is actually running, so you can easily add it to your portfolio or share with people.
There are alternatives to heroku, but I choose it because I was looking for a free service and wanted to be able to deploy really fast… there is also a nice freecodecamp article that walks you through all the steps.
I guess that something like ngrok might work too, but never tried it.
One of the requirements for testing your solutions, is for it to be publicly available, as stated in the lesson page:
When you are done, make sure a working demo of your project is hosted somewhere public. Then submit the URL to it in the Solution Link field.
When using a service like repl.it they take care of that part for you, because they make your project publicly accessible.
But since you are developing it locally, it’s up to you to figure it out how to submit FCC a live version of your project.
Generally that means deploying it, or as I said before make a tunnel from your local computer.