Setup linux kernel for beaglebone black

Hi

I’m Nazri.I’m new to beaglebone.I want to do cross compile for beaglebone black.For my understanding,I need to install linux compiler at Pc and create boot and rfs at SD card and install at beaglebone black.I’m confuse in beagleboard getting started note that need to download the Debian image.It still need to do download the Debian image if I plan to apply cross compiler?

Rgds

Nazri