Am I supposed to copy paste the information to the bottom of /etc/nginx/nginx.conf? Or erase everything in the /etc/nginx/nginx.conf file and replace it with the information at the bottom of shorturls.redwerks.org?
I do not know what your site's nginx config looks like so I cannot answer. It's supposed to be combined with whatever site config is currently hosting your MediaWiki installation.
Am I supposed to copy paste the information to the bottom of /etc/nginx/nginx.conf? Or erase everything in the /etc/nginx/nginx.conf file and replace it with the information at the bottom of shorturls.redwerks.org?