

Know that doing this is not advised and your computer will now be directly accessible to the Internet. As long as you’re fine with the potential for vulnerabilities and that risk or just don’t care:
You need to setup port forwarding on the local router for the computer you want to connect to and check the docs for origin_web_ui to include “wan” (Internet). Docs also describe encryption configurations. https://docs.lizardbyte.dev/projects/sunshine/latest/md_docs_2configuration.html#port
Know that your network router (like 192.168.1.1) keeps everything on your network from receiving any connections that weren’t already requested by a computer or phone on your network. Port forwarding opens a hole into your network and that computer now has to protect itself so keep it updated, especially sunshine, and I’d recommend not turning off ufw but just adding some rules to allow the sunshine traffic.
If you want to use sunshine over the Internet you can