KB#1: I downloaded action for InboxRULES but I don't know how to install it

Prior to evaluating (e.g. save message) action it's necessary to download and install InboxRULES engine according your environment (client side or server side version).

The best way is to install bundle version of InboxRULES which contains all actions and restrictions we have. Once you have InboxRULES installed then you can download latest actions or restrictions separately.