I'm confused trying to get SCALE to work

Hi, I'm trying to get SCALE to work but I'm so confused by what they mean by PATH and I'm stuck.

https://github.com/spectral-compute/scale-docs/blob/master/docs/manual/how-to-use.md

I'm at the CMAKE step.

This is the official guide I'm following. I do understand what they mean by SCALE_PATH though as that is clearly explained but PATH is just very vague to me or I'm just misunderstanding it completely.