documentation enhancement

README.md

@@ -34,6 +34,19 @@ Add our helm repository[^1]:
 helm repo add nextcloud-onlyoffice https://open.greenhost.net/api/v4/projects/1/packages/helm/stable
 ```
 
+Add the dependencies repositories:
+```console
+# nextcloud chart
+helm repo add nextcloud https://nextcloud.github.io/helm
+# rabbitmq chart
+helm repo add bitnami https://charts.bitnami.com/bitnami
+```
+
+Fetch the chart dependencies:
+```console
+helm dependency build
+```
+
 Then install the chart:
 
 ```console