How to use AD 676 Analogue to Digital IC
Why did you choose the AD676 in particular? It's a 16-bit ADC, which is much more than you need. A potmeter rotates over about 270°, so an 8-bit ADC would give you a resolution of about 1°. Nowadays it's often easier to find a 10-bit ADC, and they don't cost much more.  

Normally you should also look at the ADC's speed, but for reading a potmeter 10 samples per second should do and any SAR (Successive Approximation) ADC will do here (most will easily be a thousand times faster).

How do you want to interface it to your microcontroller? I2C, SPI?
A standard serial protocol makes it ridiculously easy to interface your ADC with your microcontroller. As an example the following "schematic" from the Microchip MCP3021 datasheet:  

  

The MCP3021 is a 10-bit ADC which interfaces through I2C. It comes in a 5 pin SOT23 package:  


  2 x power (Vdd, Gnd)
  2 x I2C (SDA, SCL)
  1 x Analog input  


That's all you need.