Nginx.conf file

After installation I get this warning – SecuPress: Your server runs?Nginx. You have to edit the configuration file manually. Please remove all rules between?# BEGIN SecuPress?and?# END SecuPress?from the?nginx.conf?file. Why & How is Secupress changing the nginx.conf file, on the server. This is an issue as my server runs other sites. My server runs Plesk, so where do I make these changes? No documentation on it.