Kubera is actually very close to Ishana who is worshipped for Moksha. Angaaraka is close to Nairuthi which is on the South side (Rakshasa moola). In the name of talking, manipulating and handling business we may be doing so many adharmas. Doing this may lead to Rakshasa sthaana. However, when you build your character, grace and knowledge as second to none, this can lead to Moksha sthaana. This is Kubera.
So what is the Kubera yantra? Your body. Your body becomes a Kubera yantra when you have an exceptionally unique character – and this is Sri Vidya.