I have not been able to find where to change the edge screen when screen is off. How can I do this?

[AC Question]

I have not been able to find where to change the edge screen when screen is off.

I bought one of the flip cases for my note edge. When I close the case, it turns the screen off. However, the edge screen turns on with the date and time and pink/purple bars.

How do I change this pink/purple screen, or can I make it so it does not come on every time I close my case?