Before executing the checkmate, the stronger side should move their king to the third line -- that is, two ranks or files away from the enemy king -- as near the enemy king as possible. When checkmating with a king and queen, having the kings directly opposing each other or separated by a "knight's move" will work.
In the diagram above, white has accomplished this after 8. Kb6 Kc8. White now has a checkmate in one move, which you should spot before continuing to the next page.
