Well first there's the TSA background check, then in order to get a FAA commercial you have to have a FAA private. Have your CAA verify your license to the FAA and you walk in to a FAA office and walk out with a private certificate. But before you walk in to the FAA office, pass the regular FAA IR written test. Then when you walk out of the FAA office your certificate will say "US TEST PASSED" and you'll have an IR on your private certificate. Then pass the commercial written, complete 20 hours of flight training (I'm guessing you want a MEL) and pass a checkride.