It would probably help if you said a little more about what you're interested in specifically in philosophy. What kinds of questions grab you? Philosophy is a pretty diverse discipline in terms of topic (it's not clear to me what the metaphysics of grounding and the ideal form of the state have to do with each other), and trying to slog through stuff that you aren't interested in will probably result in your abandoning the project.

If you want something introductory, I'm told that Bertrand Russell's "The Problems of Philosophy" is pretty good. You may also want to consider finding a recording of a philosophy class on a topic you are interested in somewhere, since that kind of material is pitched at a student rather than an expert.

I also really don't think it's at all necessary or even desirable to go in temporal order. I'm pretty sure most professional philosophers have not read all important historical figures, and certainly not in order. Plus, a lot of historical texts are going to be very difficult to understand without guidance from an expert--I mean, even experts have deep disagreements about how to understand most philosophical texts, and I highly doubt a beginner is going to be able to make anything of Aristotle's Metaphysics or Kant's Critique of Pure Reason. No matter how smart you are, that stuff is tough.