First thing to do is break this into individual steps/behaviors...
So start off with getting the prox sensor working... and outputting specific 'values' to the serial monitor.
I would image after that.. the rest is fairly easy?
Just a bunch of IF (maybe switch/case) statements that check the returned value against a threshold you declare as a new 'animation/pattern' effect on the strip of choice.
What type of LED strip are you talking about here? Like an individually addressable Neopixel/Dotstar led strip?
A single color led strip?
An RGB non-addressable led strip?