No videos that I can think of. Virtual devices can be anything so it's a very wide topic.
I can write up a quick example that I use - in this example we want to control a wifi fan
Step 1: install the custom driver
see video: https://www.youtube.com/watch?v=nSNuz9G3F48&t=1s
This one is for apps but the process is the similar for drivers (driver tab instead of app)
Make sure its the one under post #10 here
Step 2: create the virtual device
- Goto Devices - Add Virtual Device
- Fill in Device name and Label (Lets call it "Living Room Fan vSwitch")
- Under Type - Pick Virtual Contact with Switch (under user defined section)
Step 3: expose to Alexa
Expose the Living Room Fan vSwitch using the echo skill app (you already know how to do this)
Step 4: Create Alexa Routines
Routine 1
When this Happens: Smart Home -> Living Room Fan vSwitch opens
Action: Turn on Living Room Fan (or whatever device you want turn on)
Routine 2
When this happens: Smart Home -> Living Room Fan vSwitch closes
Action: Turn ff Living Room Fan (or whatever device you want turn on)
Step 5: Test
Turning on Living Room Fan vSwitch should turn on the fan and vice-versa
Unfortunately there might be a sync issue if you turn on the fan in alexa or any other means, it will still be in the off state in HE.
Step 6: Configure Hue button
Create new button controller
Set the action for button presses
To get around the state sync issue, I would assign 2 separate buttons for off and on.
ON button - 1. Turn Living Room Fan OFF, 2. Turn Living Room Fan ON
OFF button - 1. Turn Living Room Fan ON, 2. Turn Living Room Fan OFF
This way if the switch in the wrong state it forces a quick state change first.
I found that if the switch is incorrectly in the OFF state when the fan is on, turning off the switch again without a state change will not send alexa an event and therefore nothing happens. This is my workaround for now. I'm sure someone can think of a better way.
You can easily adapt this to most alexa control wifi devices that you can't get into HE via any other means. Good luck