This link takes you directly to Chapter 14, which explains how to format references in ACS Style. Click on the link for the Table of Contents to read the entire Style Guide, which describes how to write, review, submit, and edit scholarly & scientific manuscripts.
An annotated bibliography both summarizes sources and puts the sources in context. For each source you cite, you include a paragraph that discusses the content of the source, your evaluation of the source, why you chose this particular source, and how this source relates to the other sources in your bibliography. You can evaluate each source based on the criteria of the CUT test.
Anatomy of an annotated bibliography entry (here's the original article if you're interested):