First order is to apply for the "restricted license based on a foreign license"
This process takes about 4-6 weeks.
Take the "Foreign pilot Instrument written test", this one is different from the regular Instruument written test.
Take the written test score with you to a regional FAA office (FSDO) where you will pick up the restricted license. They will add the IR.
You will need to complete a BFR (Bi annual flight review) and an IPC (Istrument proficiency check) with a US instructor before you can fly PIC under IFR.
If you want a US CPL IR
you will need to take a FAA Instrument practical test, the Foreign IR does not carry over to the US CPL
If you take the IR test in a Multi you will get both the Single and Multi IR.
You will be required to have a visa for any flight training leading to a Private, Instrument or Multi engine rating.
As to where you can do this?
Click on my username then "my homepage" to the left here......