Those use a common type of headset, so it should have a bearing retainer in each of the two cups that are pressed into the frame. A retainer is a metal ring that holds the ball bearings, and it will need to be in the cup the right way so the balls can roll freely, instead of being pinned against the "spine" of the metal ring.
A cone rolls against the ball bearings. The lower cone is still pressed onto the fork crown like usual, and there may be a plastic seal that sits on the lower cone to shield the bearings. The upper cone slides down the fork, possibly with a plastic ring to shield the bearings from direct dirt & water, and it's centered on the fork's steertube by a wedge ring with a split in it.
Above that, you have spacers and the stem, then the top cap and bolt. When everything's assembled, the top end of the fork should be recessed down into the stem or topmost spacer about 3mm. Apply a light pinky-finger amount of torque to the top-cap bolt, then clamp the stem to the fork and rotate the bars to make sure it's not grinding or dragging, which most likely would indicate a bearing retainer is upside-down.