Tap the place where you would like to detonate a missile.

Move your finger away and look at where you tapped. The sight should be displayed.
A missile will launch from the defense base to the sight, causing a big explosion.

Items will fall towards the base by themselves.
Protect them so that they are not destroyed.
Items are acquired when they land at the base.

Tap anywhere on the screen.

The result screen ends and the game proceeds to the next stage.
Note that while the result screen is displayed, the game will never proceed to the next stage unless you tap the screen.
So relax and take this time to race to the bathroom.