Help Needed with One for the Road Blanket

Very new to mosiac crochet and came across the free pattern of one for the Road blanket by Martin Up North. Now, I am confused, is the blanket made in overlay mosiac crochet or inset mosaic crochet?

Did he work in the back loops and still do a chain 2 space? I am very confused by the images of the work because mine does not look like it. Also, it doesn't say anywhere on the pattern what kind of mosiac it is.

https://martinupnorth.com/2019/02/08/the-one-for-the-road-blanket-free-pattern-inside/

Can anyone who has made this before help me out?