Didn't you just ask this?
No, the first step is a Class One medical from the CAA in Gatwick (current cost £450?). Without that, you won't be flying commercially. The required standards for eyesight, hearing etc are described on the CAA website. If you have any doubt about (eg, your eysight) get checked out at an opticians first. It will be a lot cheaper.
Next step - a GAPAN test to see if flying really is for you.
After that, a PPL (3 weeks in the States is one of the best ways) to see whether you are as keen as you think at the moment. You may decide not to go down the commercial road and stay as a private pilot. You may hate flying and change your mind.
After that - now it's time for you to do some work. Everything I've mentioned so far has been discussed ad nauseum on this forum. Seek and ye shall find. Regarding, for example, modular v integrated - there is no 'best' way. Just the best way for you and your circumstances. I'd also suggest buying Clive Hughes' book (it's one of the cheaper purchases you'll make) again, details via PPRUNE search engine.