I pieced it all together from searching and finding this thread: Better Dimmer Device - #6 by twack
Basically, log into the API, create the new device type for the virtual dimmer, paste the code for the Better Virtual Dimmer. Save, publish.
Create a new device, use the new virtual dimmer device type (should be at the bottom of the type dropdown).
Create the smartapp in the API, paste the code of the Dim With Me smartapp. Save, publish.
Install the smartapp from the SmartThings app (Marketplace > SmartApps > My Apps).
Pick the virtual dimmer as the master dimmer, and the bulbs as slave dimmer switches.
References:
I’m loving the new “From Code” and “From Template” options when creating a new SmartApp / DeviceType.
Users don’t have to be instructed to fill out bogus information and then replace the resulting code with code anymore.
The new instructions are:
Login at http://graph.api.smartthings.com
Go to “My SmartApps” or “My DeviceTypes” and click on the “+ New SmartApp” or " + New SmartDevice" button on the right.
On the “New SmartApp” or “New SmartDevice” page, Select the Tab “From Code” , Copy the xxxxx source code from GitHub and paste it into the IDE editor window.
Click the “Create” button at the bottom.
Click the blue “Save” button above the editor window.
Click the “Publish” button next to it and select “For Me”. You have now self-published your SmartApp or SmartDevice.
Open SmartThing…
Virtual / Simulated Device Types are functional “Things” but are not physical devices you have. Installing them allows you to control them via SmartApp’s just as you would a physical smart device.
Creating Virtual Devices - On/Off Switches
There are many reasons you’d have the need for a virtual switch.
You want one switch to control multiple other switches and/or commands.
You have a multi relay device and want to control the relays individually. (currently ST doesn’t support this)
You could use virtual switches the same way you’d use Hello Home Actions, to take care of multiple actions or state changes with the change of your virtual switch state.
To create a Virtual Switch
Login to the IDE @ https://graph.api.smartthings.com/
Click “My Devices”
Click the “New Device” Button
Ente…