The CPT is a standardized assessment; if the CPT is interrupted at any point, you will have to start the entire task over again. Avoid interruptions by putting your iDevice into “Do Not Disturb” mode before you start the CPT.
At the start of the CPT, you will be shown a symbol with 5 dots; this will be your target. The goal is to tap the screen as soon as possible when you see the target. You can tap anywhere on the screen, but be sure to tap using only one finger. Avoid tapping the screen on “non-targets” - symbols other than the 5 dots.