How – The Guest Filesystem

As RMS has told us, Linux, uhm.... GNU/Linux, is more than just a kernel
You need a filesystem to boot up your kernel on
Several pre-compiled
Instructions and tools on how to create your own
Root filesystem is just a file. Create it with dd, mount with loop, install to that filesystem
Easier to start off with a pre-compiled

As RMS has told us, Linux, uhm.... GNU/Linux, is more than just a kernel