Installing Qubes and coreboot

Hi everyone
I have a Lenovo x-230 which has qubes on it and I bought it with coreboot which seemed like a good idea at the time. I am wanting to do a fresh install of the latest stable qubes rather than upgrade my existing qubes.

Please excuse my novice status with this. Normally when I install something, of course, I just go into the boot menu which I think is F1 on the Lenovo and boot from a USB and install from there. Trying to do this with coreboot however takes me into an unfamiliar menu which I don’t have in front of me now, but there was no way to boot from a USB and a memory stick I had inserted did not show up. Can someone tell me how I go about installing Qubes on a laptop with coreboot? I’ve searched but can’t find anything definitive and I don’t want to brick this laptop obviously.

I apologise if this is a real beginner question but I am genuinely stumped. As I said, the idea of coreboot was a good idea at the time although seeing as though I knew nothing about how to work with it shows that maybe I was a bit hasty.

I really appreciate it if I can get some advice or pointers to links here.