Quick Sketch is a small mode available right from the beginning of the game. In this mode, you and your partner will quickly go through drawing various Pokémon. In this mode, you get no choice over the tools used, and you progress simply by following what was shown on the top screen. Sometimes, you will get given construction shapes on the bottom screen to help you begin, but you can change to the template with the B button if you do so wish.
These drawing tasks are often very simple, with some just requiring the outline of a Pokémon, and won't take long. When you complete each of the drawings for the first time, however, you unlock the template for use in Free Paint mode.