Porting to Snapdragon 8cx SoC

Hello, community! I am reaching out because I have a Thinkpad X13s with a
Snapdragon 8cx Gen 3 SoC. I have been unable to get any operating system to
work so far on this machine. I have done a fair amount of coding and
debugging in C. However, I have never ported an operating system before. I
am in my senior year at university and I would like to undertake this as a
project. I have an x86_64 machine running FreeBSD which I can use to help
me in this endeavour. However, since I have never done this before, I lack
the domain specific knowledge on what I will need in order to be
successful. Any tips on how to get started would be greatly appreciated.
Thank you very much!!