Mostly in the recommended reading order, but he listed some notes on their importance or when they can be skipped, etc. with many of the sources, particularly at the start of the list.

This should take you up through where you were at State and Revolution and where to go next. I have to say that the recommendation others have given for Black Shirts and Reds is also a very good place to start for the reasons they gave.

Almost all of these can be found on the internet archive, Anna’s Archive, or you can ask around on lemmy.ml or lemmygrad.ml for free digital copies. While some people prefer physical books, there shouldn’t be any need to pay for these unless you want to.