What FB was refering to was to check that there is no play in the headset after you've adjusted it. Put the bike on the ground, lock the front brake and try to move it fore-and-aft. Place your fingers around either the top bearing or bottom bearing and be sure there is no movement there when you thy to move the bike the bike.

If the fork turns freely but there is no headset play, center the stem over the front wheel and tighten the stem bolts to the proper torque.