diff --git a/docs/production/install-existing-server.md b/docs/production/install-existing-server.md
index 3ed151db94..1f23ff6f63 100644
--- a/docs/production/install-existing-server.md
+++ b/docs/production/install-existing-server.md
@@ -29,10 +29,17 @@ one created by Zulip into it:
 ```shell
 sudo cp /etc/nginx/nginx.conf /etc/nginx.conf.before-zulip-install
 sudo wget -O /etc/nginx/nginx.conf.zulip \
-    https://raw.githubusercontent.com/zulip/zulip/master/puppet/zulip/files/nginx/nginx.conf
+    https://raw.githubusercontent.com/zulip/zulip/master/puppet/zulip/templates/nginx.conf.template.erb
 sudo meld /etc/nginx/nginx.conf /etc/nginx/nginx.conf.zulip  # be sure to merge to the right
 ```
 
+Since the file in Zulip is an [ERB Puppet
+template](https://puppet.com/docs/puppet/7/lang_template_erb.html),
+you will also need to replace any `<%= ... %>` sections with
+appropriate content.  For instance `<%= @ca_crt %>` should be replaced
+with `/etc/ssl/certs/ca-certificates.crt` on Debian and Ubuntu
+installs.
+
 After the Zulip installation completes, then you can overwrite (or
 merge) your new nginx.conf with the installed one: