The ActiveNoise speaker is a directional speaker: it projects its sound in one centred direction.
Microphone
Point the microphone towards the source of the noise. There should be some distance between the microphone and the noise source: at least 5 metres.
Speaker
Point the speaker towards yourself, or towards the place that needs the noise cancelling.
Fine-tuning
Most likely, the directions of the microphone and speaker need some adjustment to optimise the result.
You can find more information in the installation guide under Documents (after logging in).