Task: I'm going to Barcelona with my mother, thus I'm searching for a hotel in Barcelona for four nights from November 1st to November 5th, 2023 in the booking.com app.
Steps:
Open the booking.com app
Click on the destination search bar at the top of the screen
Search for Barcelona 
Click on the first result
Click on the dates section
Click on the 1st Nov
Click on the 5th Nov
Click on the select dates button at the bottom of the screen
Click on the person section
Click on the - icon of the children section
Click on the - icon of the children section
Click on the apply button at the bottom of the screen
Click on the search button