The pickup place of the car is the same place where the rental agreement will be signed , or the rental car counter is at the airport and is necessary do it before take the shuttle bus to the car pick up point??

Just walk out to the rental car shuttle after you pick up your bags. It is on the island in the middle of the 8 or so lanes of traffic. Make sure you go to he rental car pick up area. There is a separate area for hotel shuttles.

Everything is located outside the airport, so first take the shuttle to the National Car Rental location.