Power mobility scooters that use U1 or larger batteries (as opposed to lift-off style battery packs) are shipped with their batteries usually in place but not plugged into the scooter. This is to ensure that the scooter cannot be accidentally powered up during shipping.
To check, you'll usually have to remove a cover or shroud to expose the batteries and their wiring.
Then, inspect the batteries. You'll see that the wires coming off of them end in various styles of connectors depending on the brand and model of the scooter. You'll also see that the mates to those connectors are nearby.
WITH THE KEY REMOVED, plug the battery cables into their mates. Reinsert the key and turn it to make sure the scooter control console lights up. Turn the key to the off position, replace any covers or shrouds that may have been removed and your scooter is now ready to ride.