Welcome to the forums! The syllabus is for someone taking the Complete Course—you'd also have access to other resources besides the guides. So I wouldn't exactly follow that if you have only the guides.
In any one guide, yes, you will move through that guide in order. But you won't literally just go 0 through 9 for the overall guides.
Guide 0 Roadmap has a bunch on how to study, so use that generally on the earlier side. Keep looking at the Table of Contents and use what you think you need when you think you need it.
Guides 1 through 5 are the quant guides and I would generally work through those in order (as the syllabus does too). If you haven't done any GMAT studies yet, you'll want to start with the Data Sufficiency appendix at the back of Guide 1.
Guides 6, 7, and 8 cover the three Verbal question types. I wouldn't do these books one at a time (eg, I wouldn't do all of guide 6 and only then start guide 7). I would use these three relatively simultaneously—do some SC and RC this week, then maybe some SC and CR next week, that kind of thing. Your brain will learn better if you are moving around among the question types. (Again, within one guide, go in order.)
And Guide 9 is IR/Essay. Most people leave these two sections until somewhat later in their studies, since these sections aren't as important on the GMAT. I would start them when you're maybe halfway through with the Q and V stuff—start to weave in IR/Essay in one or two study sessions a week.
Re: OG, contact our student services team (
gmat@manhattanprep.com) to get the OG2019 problem list.
Good luck with your studies!