Sherry,
To download at one off selected times:
In the Scheduler window:
Select "Start Scheduler at......."
In the timer underneath: Click on the Hour and adjust. Click on the Minutes and adjust.
Select "Once at....." and select the date.
In "When scheduled download begins" I just selected the first option.
In "After scheduled downloads stopped/finished" you can select none, 1, 2 or all options. (I selected none of them in this instance because I still wanted the computer on. If I was scheduling for when I went to bed I'd just select the "turn off computer" option.)
Apply the settings.
To schedule your files:
When you right click your files and select "Download ALL with DAP" they go into the "paused" status. Open the main DAP window. Click on "paused" to see all the files you have selected.
Highlight them all and drag them into "Scheduled". You may get a popup that says only files sorted by "status" can be moved. If so, just above the selected files click on "status" button. Now you can drag the files into "Scheduled".
You can now close off this window. The DAP icon will remain on the toolbar.
At the selected time the downloads will start.
If you need help just holler.
ETA: Make sure the "current time" is correct in the Scheduler window of DAP.