(Question) CSS3 parsing procedure, where does parsing Declarations go?

I have a question about http://dev.w3.org/csswg/css-syntax.
It's written in the document that inside Simple Block are declarations.
There's actually instruction on how to parse Declarations. However it
doesn't seem to be anywhere in the overall procedure:
Stylesheet -> Qualified Rule -> Simple Block -> Component Values

There's no path from the Stylesheet that leads to a Declaration, they just
don't belong anywhere in the AST tree that's supposed to be parsed.
Am I missing something? Why is it that way? Like, where am I supposed to
call the "ParseDeclarations" function in my parser? Does it have to be
parsed separately, away from the AST according to the standard? That's
super weird.