Its very straight forward...............
Approach a Flight School.....have them send you the Theory Books........study them on the Jet on the way to the US.......do the Cyber Exams at the Airport........[Remember the Questions and Answers are supplied in the books]....do a Basic Handling Test with the IFR Component [can be done on a VFR R22....], VOR/NDB/ILS and then a face to face verbal with the Examiner..........FAA ATPL.
If you wish me to send the name of the school and Examiner that I would reccomend....drop me a private message.