diff --git a/README.md b/README.md
index 19b8141..cd0d353 100644
--- a/README.md
+++ b/README.md
@@ -25,6 +25,13 @@ WordPress demonstrates a persistent website and MariaDB database. Bind
 password in each environment; do not commit it to this repository. Complete
 WordPress installation privately before exposing the site to visitors.
 
+Set `WORDPRESS_PUBLIC_URL` to `https://demo.citadelplane.com/wordpress` or
+`https://preview.citadelplane.com/wordpress` in the corresponding Citadel Stack.
+WordPress lives under `/var/www/html/wordpress`, using the existing named volume,
+so its public path and Apache's directory layout agree. The reverse proxy must
+preserve `/wordpress/` and forward `X-Forwarded-Proto: https`. Site and admin URLs
+are derived from this binding; use HTTPS and omit the trailing slash.
+
 Web ports bind to loopback for access through a host reverse proxy or SSH
 tunnel. Database ports are not published. Supply these non-secret variables in
 each Stack to avoid host-port collisions: