For Part II you write in where you reside on Line 9 and on Line 10 the withholding rate from to 30% depending on which article of the US/Trinidad tax treaty applies to you.u00a0 Then write in the type of income and the treaty article that applies to your income. The most common are Article 9 for business profits or Article 11 for personal services, but not knowing your particular circumstance I can't say if one of those is correct for you.Part III only requires your signature and the date signed.u00a0 You are attesting that the statements in Part III are true.