diff --git a/03-installing-osm.md b/03-installing-osm.md
index a69bdefce0f8f124b16b77178da088aa53e4ef65..ffdd1a8e1a8ce5ab5c6cec4b860f8be4a498e4f8 100644
--- a/03-installing-osm.md
+++ b/03-installing-osm.md
@@ -374,6 +374,38 @@ To install Charmed OSM with the HA controller the following argument will be pas
 ./install_osm.sh --charmed --vca manual-controller
 ```
 
+#### Using external DBs
+
+Charmed OSM supports the usage of external DBs. For this purpose, relations to the DBs should be removed:
+
+```bash
+juju remove-relation nbi mongodb-k8s
+juju remove-relation lcm mongodb-k8s
+juju remove-relation ro mongodb-k8s
+juju remove-relation mon mongodb-k8s
+juju remove-relation pol mariadb-k8s
+juju remove-relation pol mongodb-k8s
+juju remove-relation pla mongodb-k8s
+juju remove-relation keystone mariadb-k8s
+juju remove-application mongodb-k8s
+juju remove-application mariadb-k8s
+```
+
+Now, add the configuration to access the external DBs:
+
+```bash
+juju config nbi mongodb_uri="<MongoDB URI>"
+juju config lcm mongodb_uri="<MongoDB URI>"
+juju config ro mongodb_uri="<MongoDB URI>"
+juju config mon mongodb_uri="<MongoDB URI>"
+juju config pol mysql_uri="<MySQL URI>"
+juju config pol mongodb_uri="<MongoDB URI>"
+juju config pla mongodb_uri="<MongoDB URI>"
+juju config keystone mysql_host="<MySQL Host>"
+juju config keystone mysql_port="<MySQL Port>"
+juju config keystone mysql_root_password="<MySQL Root Password>"
+```
+
 ### Installation from source
 
 TODO: Under elaboration.