Vehicle slots
Slots represent the number of vehicles you can own. You start with 2 vehicle slots, but only 1 vehicle can be available to you at first. To own a fleet, you need to buy more slots in the Premium Store or win them from crates.
In Premium Store, look for slots in Services. A slot costs 99 MC.
Parking
Parking allows you to save a specific spot on the map where your car will spawn. You can park anywhere except for Green Zones.
To save your spot, use the /park command while inside the car.
This makes it easy to spawn your ride exactly where you need it without trekking back to a garage.