How to use ILockApplicationHost to customize LockScreen behavior

Dear all,
when I was searching for a way to do some customization over the lock screen, I found this page on MSDN, which says 'You can create an app that acts as the lock screen, allowing greater user personalization.'
However, there is not many turtorials on this in C++. What's worse, I am not experienced in UWP at all, and get really confused when I found that ILockApplicationHostStatics::GetForCurrentView is not static, and that all its methods are pure virtual. Should I provide implement a sub-class to make it work? Then how do I register it to get invoked by the system? I'd be really grateful if you would send me link to some sample code or tutorial pages in c++. (Or maybe c# as well, for I cannot even find c# tutorials on this so far……)
Many Thanks.