Power Pins

• VCC - this is the power pin. To power the board, give it the same power as the logic level of your microcontroller - e.g. for a 5V microcontroller like Arduino, use 5V
• GND - common ground for power and logic

I2C Logic Pins

• SCL - I2C clock pin, connect to your microcontroller I2C clock line. This pin is 3.3V and 5V compatible, and there's a 10K pullup on this pin.
• SDA - I2C data pin, connect to your microcontroller I2C data line. This pin is 3.3V and 5V compatible, and there's a 10K pullup on this pin.
• STEMMA QT - These connectors allow you to connectors to dev boards with STEMMA QT connectors or to other things with various associated accessories
  

Analog Pins

• A0-A3 - ADC Inputs, Connect these to the voltage you want to measure
• Out - DAC Output. Connect to a circuit to create a voltage

Other Pins and Jumpers

• OSC - Oscillator input/output. Outputs the oscillator signal used by the ADC. You can use it to  supply an external oscillator using the EXT jumper
• EXT Solder Jumper - OSC Switch. Short to use an external oscillator
• AD0, AD1, AD2 Jumpers - I2C Address jumpers. Bridging the solder jumpers on the back will allow you to change the I2C address from the default 0x48 (72) to one between 0x49 (73) and 0x4F (79). 

Shorting A0 will add 1 to the address, shorting A1 will add 2, and A2 will add 4. For example

0x48 + 1 (A0) + 2 (A1) = 0x48 + 3 = 0x4B

or

0x48 + 1 (A0) + 4 (A2) = 0x48 + 5 = 0x4D