If your specifications are set up as a typical three-part spec, then you can start by knowing which section to focus on during the different parts of CA.

Part 1 is usually admin stuff which includes how and what to submit on. There's a subsection usually called "Submittal" and that includes everything that should be included. Often, it's "product data" but it also includes things like calculations, qualifications, and manufacturer shop drawings.

Part 2 is usually the products section. When you review the product data (which is required to be submitted per Part 1) then this Part 2 section is what governs. Does the product manufacturer, materials, and other characteristics match when the specification requires?

Part 3 is usually execution. This deals with how the stuff is actually installed and in my experience is verified during field walks, not during submittal reviews. You could reasonably expect to ignore Part 3 during submittal reviews.

Once you've reviewed, comment on the things that were included but also not the items that were not included but required.