The connections are very easy. The ATtiny has 6 pins taht we could use and a supply of 3V from the battery and GND pin. Don't worry, the chip works fine at 3V and the same for the rest of the components. The buttons have a pulldown and are conencted to pins PB0, 2 and 5. The OLED display needs i2c communication and that is created on pins PB4 and PB3 for data and clock. We have the SPI port for ISP programming with the Arduino.