Audio/Video receiver plugins are associated with Media Center host.
To select and configure plugins all you need to do is edit your host configuration and go to the advanced tab. (See Configuring Yatse for details)
Click on the 3 dots button to select the Plugin.
If you already have a plugin selected you can directly click the configure button
Choose the plugin from the list.
If no plugin is available or your receiver brand is not listed, then press the more button to download some.
Please note that not all receivers are available but the API is open source and documented on: Github so anyone can build new plugins.
You should check this website and Social Networks for announcement when new plugins are made available.
Upon selection, the plugin specific dialog will be shown to configure it.