The Arduino IDE is an application program that allows you to write a program, compile it, and download it to a microcontroller. To start the program on our Raspberry Pis, you can select the program from under the Raspberry "applications menu" in the upper right hand corner, like this
We have a few different microcontroller boards, and the Arduino IDE needs to be configured so that we can communicate with the board we have connected to the Raspberry Pi. The configuration is made under the Arduino IDE menu items "Tools | Board:" and "Tools | Port:". Here is a guide to these settings.
Board: "Arduino/Genuino Micro"
Port: "/dev/ttyACM0 (Arduino/Genuino Micro)"
Board: "Arduino Leonardo"
Port: "/dev/ttyACM0 (Arduino Leonardo)"
Board: Arduino Nano
Processor: "ATmega328P (Old Bootloader)"
Port: "/dev/ttyUSB0"
Board: "Arduino/Genuino Uno"
Port: "/dev/ttyUSB0"