How to get started porting std to another target?

Yeah, this is painfully vague. I want to find some resources that show the process of porting std to another target, as i want to try my hand at porting std to the 3ds. Any resources to get started?

I'm not sure as far as guides, but at a base level you could search Github for other "add target" or "tier 3" pull requests to see what they had to do. As one relevant example...