Portable device and method for restricting use of portable device

A portable device, comprising: a touch screen; a storage unit configured to store instructions; and at least one controller. The controller is configured to execute the instructions to: receive, via the touch screen, a first user input for selecting a first application from among a plurality of applications installed in the portable device; receive, via the touch screen, a second user input for setting a time period during which a restriction is to be applied to the selected first application; in response to a first notification relating to the first application occurring outside the set time period, output, via the touch screen, a first graphical indication indicating an occurrence of the first notification; and in response to a second notification relating to the first application occurring during the set time period: store the second notification without outputting a second graphical indication indicating an occurrence of the second notification before the set time period is expired; identify whether the set time period is expired; and in response to the set time period being expired, output, via the touch screen, the second graphical indication based on the second notification.