Unless you request otherwise, a message is immediately sent when you click on the Send button. Click on When to Deliver... if you want to schedule delivery for later.
When PRESTO goes to deliver a scheduled message (particularly in a series), it is possible that its TO-list will be empty. In particular, if its entire TO-list is the people who match a Search, it is possible that no one will match on a given day. When this occurs, the message is simply not sent that day.
Instead of clicking on the Send button after setting up a scheduled announcement, you could click on a Save Draft button at the top of the page. If you later select this message from the Drafts folder and Send it, the schedule settings you saved will be applied then.
These options apply the selected condition daily, starting when you click on Send and lasting forever.
To setup an Each-event series, enter the desired Days Before on the Each-event line. This kind of series is good for automating sending of a "Please signup" announcement each time you have a new event. For example, if your next event starts in 30 days and you had previously setup a 21 Days Before series, the delivery for this event would occur in 9 days. (Note: don't forget to Publish the event before the announcement goes out).
To setup an On-site-tasks series, enter the desired Days Before on the On-site-tasks line. This kind of series is good for sending people please-showup reminders. So normally, you would include !p.signups! somewhere in the message. Every day, it scans the signups for Main On-site Tasks and Background On-site Tasks, sending a message to each person that has signups on the indicated day. For example, suppose you set Days Before Task to 3. If on day 0 no one happens to have signups on day 3, then no messages are sent on day 0; if on day 1, 2 people happen to have signups on day 4, 2 messages are sent on day 4; and so on.
Notes:
To setup one delivery, select Schedule delivery and enter the date you want the message delivered. For example, you could schedule a message to yourself if you wanted to be reminded to do something.
To setup an Every-n-days series, enter a start date and how frequently the announcement should be repeated. If you do not specify an end date, the announcement will be repeated until you delete it or change its schedule settings.
As implied above, this kind of series can be used to setup specialized activity-based deliveries. For example, suppose you want to poke people in the current event who are behind on completing their planning actions. Suppose further, you want to do this 2 weeks before those actions are supposed to be completed by. To do this, create and send a message:
After you click on Send, the announcement is placed in the Pending Announcements folder. Until the announcement (or the last of a series) is delivered, it will remain there. To see what is in the folder, click on Top-level menus->Right MORE->Manage Email Folders.
From the manage-folders page, you can cancel an announcement and see when its next delivery is scheduled for. You can also click on its Update icon if you want to modify what is delivered or when.