It's probably not adjusted properly from the factory. Adjustment is best performed with the front wheel removed and the bike held by the frame off the floor as in a bike stand. Loosen the top bolt, then loosen the stem pinch bolts. Slide the stem up a few millimeters so the fork is loose, then tighten the top bolt until you feel no play in the fork when you grab it by the dropouts and push it forward and back. Center the stem and tighten its pinch bolt(s). Turn the bars side to side and see that the fork turns easily with no tight spots. Tighten the top bolt and re-check that the fork has no front/back play. If it does, loosen the stem pinch bolts and turn the top bolt another 1/4 turn, then re-tighten the stem and top bolt.

Edit: I guess that video was posted while I was posting this.