Problem making server blocks on ubuntu 18.04

Sorry kinda late but what that response is telling you is that the sym link already exists.

If you want to create a new one, either remove the current one or rename the one you are creating (as long as it doesn’t override with the one that already exists).

rm /etc/nginx/sites-enabled/create

then rerun

ln -s /etc/nginx/sites-available/create /etc/nginx/sites-enabled