Select the port of your Arduino board from the Tools > Port menu.
Sometimes the port will be labeled with the board name in the menu. Other times it will not. If you don’t know which port is your Arduino, you can find it like this:
Unplug your Arduino board from the computer.
Tools > Port
Note the ports, if any, listed in the menu.
Close the Tools menu
Plug your Arduino board into the computer.
Tools > Port - The new port listed in the menu is your Arduino board.