I use git for that sort of thing. My workflow for dev copies of an app is at https://gist.github.com/meatballs/f362b67712dc13d62ea0d288b03bb63a
For your new app at anvil.works, you can follow the same process as my dev-app in that workflow.
e.g.
- Create a new app at anvil.works and note its git url
- Add that url as a remote on your local git repo
- Force push to that remote
- Open the app at anvil.works and fix data tables problems