What should I do to install the automatic toll collection system in Miami? My reservation is FL785BE. Thanks in advance.

You must go to a SunPass station and buy it is not expensive, it costs between 8 and 12 dollars. They will apply it with your credit card and they will load the rental car plate to your account and that's it. It is the best thing to do but Alamo will apply a much more expensive charge.

Present the credit card and everything is automatic

In general it is automatic, however, it is always worth mentioning when removing the car you want toll charges to be made by the license plate.

Is automatic

It's usually automatic, you only pay on your card.