trying to make a script for sub notifications.

[Stoned Penguin]

So i'm trying to make a script for a friend where whenever someone subs it turns on a source for a texture around his cam and which texture depends on the sub tier.
But i'm having trouble figuring out how to make a call for the script to change visibility of a source or just how to change the order, basically because he want the current texture to stay until next sub.
Any help would be appreciated.