diff --git a/doc/check-certificates.md b/doc/check-certificates.md
index 52f5e51..58151f3 100644
--- a/doc/check-certificates.md
+++ b/doc/check-certificates.md
@@ -34,6 +34,10 @@ in `global-config-overlay`, these are the parameters:
 * `CertRenewUrl`: the url to download certificates from
 * `CertWarnTime`: on what remaining time to warn via notification
 
+> ℹ️ **Info**: Copy relevant configuration from
+> [`global-config`](../global-config.rsc) (the one without `-overlay`) to
+> your local `global-config-overlay` and modify it to your specific needs.
+
 Certificates on the web server should be named by their common name, like
 `CN.pem` (`PEM` format) or`CN.p12` (`PKCS#12` format). Alternatively any
 subject alternative name (aka *Subject Alt Name* or *SAN*) can be used.