According to http://codex.simple-press.com/codex/plugins/plugin-basics/using-plugins/ I should …go into the Simple:Press administration menu where you will find a Plugins section. In the plugin panel you can activate which plugins you wish to use.

However, there is no Plugins section in my administrative menu. It is really odd actually.

We are using WordPress 3.9.1 and Simple:Press 5.4.2 and the only options visible are:

Forums
Options
User Groups
Permissions
Profiles
Admins
Users

What should we do to activate plugins now?