When you arrive at MCO, you go through immigration and then goto baggage claim and pass thru customs. At this point you can then either put your bags onto a conveyor belt for forwading onto the baggage claim in the arrivals area OR you can hand carry your bags up an escalator, and then onto the monorail train to the arrivals area.

Once you disembark the monorail,(which is on level 3) follow the signs to baggage claim (level 2) and onto the car-hire desks on level 1. All the car hire companies that USCarhire use are based in level 1. Once you've completed your paper-work at the desk, you wander across the road (a minute's walk) to pick up your car from a multi storey car-park.