When we’re talking of a headset, we’re talking of the whole set of parts that make the bar turns. It includes 2 Campy spec bearings, a pinch ring for compression, a top cap for dust protection and look and finally a race cup for compression (that is almost never used anymore since new forks comes with it integrated).
They’re 2 big types of headset, one being almost extinct:
The vast majority of freestyle scooters comes with integrated headset nowadays. They are automatically sealed bearings and for us, to be considered as a «freestyle» scooter, it is mandatory to have one as it takes more abuse, forgives when you ride it a bit loose and is compatible with all the aftermarket parts as it is now the standard in the scooter industry. If a scooter does not come with it, we classify as a youth one, even if it is rigid and skatepark ready
External headsets are easy to spot by being, well, external of the deck. You will see 2 black cups, one at the top, one at the bottom. Those cups are where the bearings comes and not all of them are sealed. In fact, in the scooter world, the vast majority will not be sealed as those are used on cheaper scooters.
Since the bearings comes directly in the deck, you just have to put them in. We recommend greasing everything with thick grease to avoid any frictions.
Ideally, for taking those cups out and putting them in, you need special tools made especially for external headset. We highly recommend to go to your local scooter shop or bike shop for that installation.