You all know that opto osolator boards are used to pass signal between circuits without connecting them electrically. They are great for eliminating noise problems, or to connect circuits that have different voltages.
The opto isolator is very easy to use. Since it just passes signals through it, you just hook it up between the two different devices you want to communicate. Additionally, you will need to properly hook it up to each devices power supply. The device is intended to isolate the circuits electrically, so each side needs to be powered independently.