Nodes are not create automatically under namespace/system

I've started a Hippo project using the base, simple archetype (so only cms, site and bootstrap modules). Then I've tried to install the Forge Selection Plugin by adding the dependencies to the pom.xml of the cms module as described at http://selection.forge.onehippo.org/install.html (note: I've only did the Installation in CMS/Repository section and the dependency part of the next section, but that section "Installation in HST site" contains steps that I couldn't locate in my Hippo instance.)

Maven reported no problems when I rebuilt the project, but there were no Primitive Field type "Static Dropdown" in the cms application adding a new document type. It appeared though when I exported the /hippo:namespaces/system/StaticDropdown node from the Selection Demo application and imported it into my Hippo instance.

As the documentation of the plugin speaks about "content" module and I can't see such module in my Hippo instance (version 7.9.0) I think this has been changed and the plugin is not updated yet. I'm new to HippoCMS so this is just a thought, maybe there was something that I did wrong or missed.