Task: As I had planned to stay in Dubai for a couple of days, I searched for one-way flights from Dubai on October 25 for two adults in the Kayak app.
Steps:
Open the kayak app
Click on the London in the search bar
Type Dubai in the search bar
Click on the first result
Click on the calendar section.
Click on the 25th date in October 
Click on the apply button.
Click on the traveler section.
Click plus icon of the adults section.
Click on the apply button.
Click on the search flights button.
Click on the search flights button.