I had the same issue as OP. I managed to use the image you linked, and it worked great to boot from USB.
I would like to install it into internal memory, but I'm kind of lost at this point. From what I've read online, I need to sign my kernel, copy it, and all the files from the rootfs in the image, and set that partition to highest priority to make it work.
I can paste the script I was thinking of using (it's a bit long), but I wanted to know beforehand if there was a step-by-step guide, or if I'm missing something obvious first.