Where to start with my study? Please help

[emmyloo]

Hi there. I am going to sit the GMAT in early October. I have just purchased the GMAT Official guides and planned to start my study with those. However, from reading this website, it seems there are so many other resources available that it is a little overwhelming.

I was thinking of also getting the Manhattan Guides and using those as well. My main areas of focus will be the quantitative sections. I am a native english speaking so my reading comprehension is good. It's the problem solving and maths that I will need to focus on.

Is the official guides (I bought all 3) plus if I get the Manhattan guides - is that a good start or should I be using something else?

Much appreciated!