A delivery window is a period of time where automatic communication can be sent by Armatic. Delivery windows will not have any impact on communication sent manually through Armatic.
Set your delivery windows under Account>Communication
Simply select the days you would like communication to be sent, then choose the start and end times for sending communication. Time is in 24hr format (i.e. 13:00 is 1pm). From is the first hour communication can be sent and "To" is the last hour communication can be sent.