Plugin installation
Yes, it's time to install your plugin before you actually started real development. Go to Admin area → Plugins → Available Plugins. Click Install on your new plugin.
When I go to my admin area -> plugins -> Available plugins, my plugin does not show at all, nor is there an Install button. I made sure to follow the instructions closely. And I renamed the plugin to contactus2 due to already having a contactus plugin already installed by default.
Platform version 1.5.3 (build 6341)
Installed via Softaculous