I was following the step by step in the files section about installing it in an existing linux installation but I now see where it's running Ubuntu by default.  Do I need to install Debian instead?  If so these are my options:

Debian 6.0.6 x86 Minimal v1 (gen2) The Debian Project is an association of individuals who have made common cause to create a free operating system.
	Debian 7.0 x64 Debian 7.0.0 x64 Minimal v1 (gen 2) - Min 2GB HDD
	Debian 7.0.0 x86 Minimal v1 (gen 2) Debian 7.0.0 x86 Minimal v1 (gen 2) - Min 2GB HDD
	Debian 7.3.0 x86 Minimal v1 (gen 2) Debian 7.0.0 x86 Minimal v1 (gen 2) - Min 2GB HDD
	Debian 8.0 x86_64 Minimal v1 (gen 2) Debian is a free operating system (OS) for your computer. An operating system is the set of basic programs and utilities that make your computer run. Debian provides more than a pure OS: it comes with over 37500 packages, precompiled software bundled up in a nice format for easy installation on your machine.
	Debian 9 64bit Minimal