How do I actually run uml?

Just execute 'linux' in a directory that contains the root file system (called root_fs), i.e.,
cd ~/myrootfilesystemdir; linux
If the root file system isn't called root_fs then run 'linux ubd0=whatever it's called' instead, i.e., if the root filesystem is Mandrake_rulezz_fs then:
linux ubd0=./Mandrake_rulezz

Just execute 'linux' in a directory that contains the root file system (called root_fs), i.e.,