Thanks! So looks like im getting ahead of myself. No im not moving config over i think that error is just because i added these paths from the guide i was following to the nginx.conf when troubleshooting:
ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
I just started following the guide on linode to set up an asp core website so was just following the steps and the guide didnt mention needing a domain beforehand. Sounds a bit silly now you say it of course id need a domain to generate a cert for it. So I will just set this site up with http only for now and read up more on certs before I try again.
Thanks for your help!