Global entry kiosks at MIA are now outside of the actual immigration hall, at the left end. Once you get your printout you will need to get in the global entry line at the very end (left side) nexo to bathrooms. Keep in mind that unlike other airports, inmigration checks passports on a one by one basis for global entry travelers. If you can believe it, I have more than once seen the global entry line take longer than regular immigration lines! Customs, however runs much faster for GE.