Update HOWTO.md

HOWTO.md

@@ -26,6 +26,10 @@
 
     **Note**: [Here](https://thl-cmk.hopto.org/gitlab/explore/projects/topics/Network%20Visualization) you can find all plugins from this page at a glance.
 
+    If you are done with the package installation your package repositor shouls look like this
+    ![](img/installed_package.png "Installed extensions")
+
+
 1. Rules
     You should add two rules:
     - Enable the HW/SW inventory for all your (network) devices that you want to include in the topology.