To add a new plugin, click Plugins and search for the one you want. It shows any plugins available to install. Suggest enable “Child Bridge” after installed each plug-in by spanner icon. HomeBridge will provide stand alone bridge for HomeKit. It doesn’t mess up different kind of device plugins which provide to HomeKit. The advantage is you don’t need to remove all devices from main bridge on HomeKit App while happened. Just one child bridge one device or one child bridge for a subset devices. ( https://github.com/homebridge/homebridge/wiki/Child-Bridges )

I would like to use SSH plugin be example for testing which not related to any device and It can provide a button for HomeKit app, After plugin installation and click spanner icon > “Start Child bridges”.

Once enabled the Child Bridge feature. Homebridge required manually restart the system for plugin reload like following picture.

Then click on spanner icon > “Bridge Settings”. Child bridge QR code ready for scan.

At last, just use “Camera” or “HomeKit” app on iOS to scan it and follow step one by one until you see SSH button present on HomeKit. That’s it.