HDD images

I was going to get the raw hdd image and try to boot up Haiku for the 1st time, but I’m most confused by the “Test Images” page. Under “Raw HDD Images,” there is a link to “Haiku Build Factory.” Visiting that site allows me to download a 1.27MB bz2 file - what exactly is that file?

I moved on to the haikuhost.com (housetrain) link, which seem a little more sensible - a 24.2MB raw.tar.bz2 file can be found (which I guess is the raw HDD image?).

And finally, the “NK Security” link brings me to a page where I can download a 12.73MB haiku.image.7z file. Which one would I need to write an HDD image to my HD and attempt to boot-up Haiku?