Thanks for your query and very sorry for the wait in hearing back from us.
I have located your account and there are currently no devices registered with two changes available to utilise.
If you already have the app, as mentioned in your post. All you'd need to do now is try and watch one of the live channel listings and then a message should pop up advising you that you need to register your device, this should then redirect you to a My Virgin Media web page and from there, you will be able to name the device and register it.
Once registered, you should be all set!
You are able to register up to two devices per account for our TV Anywhere service.