Why can't I send a String from Processing to Arduino over serial?

It's working the other way around, but any input I send from Processing to Arduino parses into a Byte.

I have 24 neoPixels connected to Arduino and need Processing to send "10" "5" "12" "23" "24", just 5 digits to tell Arduino which ones to light up. And I can't figure out how to do this. All it outputs is one Byte..

Anybody have an idea?

Serial input basics

Each Neopixel needs 3 bytes of data to control its Red, Green, and Blue LED.
Do you have some basic color that you want LED #10 to light up with for example?
Are the others to retain the same color when you change one?