Right now there are two community-created edge drivers for virtual devices and they work a little differently.
As your first Edge Driver, @ygerlovin ’s might be a little easier to understand.
First you will follow a link to subscribe to that channel. This will download an Edge Driver, YG’s Virtual Device Controller, to your hub.
Once it is downloaded, you will “scan nearby” in your ST app and it will be added as a device to your account, then you will see a device tile for the controller.
Now the magic happens. 
Go into the details screen for the Virtual Device Controller and it will walk you through the steps to create a virtual device.
For more details and any further questions, see that topic:
[ST Edge] Virtual Things Edge Driver
But the steps to use any custom edge driver are the same:
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follow the link the author gives you to subscribe to their channel
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wait for the code to be downloaded to your hub
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use the SmartThings app to add a new device to your hub, probably using Scan Nearby. The device will automatically choose the Edge Driver if the fingerprints match.
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Once the device is added to your hub, you can see what Driver it is using by going to its detail screen and then tapping on the 3 dots in the upper right.
- to see which custom driver channels you are subscribed to, go to
your hub device page in the mobile app, tap the upper right menu and choose Driver.