For general assistance on how to use SUbD, please post your question at the support forum kindly hosted by the good folks over at SketchUcation.
Asking your question in the forums helps other people by making it readable to everyone. Additionally you will benefit from the collective knowledge of the community and most likely get a faster response.
Also availible via the Extension Warehouse.
Purchase one license for $40 using PayPal.
A license allows one person to use SUbD on any number of machines, but the license cannot be shared with anyone else.
Incremental updates (x.1, x.2 etc.) are free.
Visit SketchUcation's forums and enjoy the great community of helpful peers and resources.