You can put downloads to Queue for download them at later time using Download Later Option. You can start the queue processing manually by 'start queue' option or using the scheduler.

To start the download queue manually Goto XDM Menu->Downloads->Start Queue. To stop the queue proccessing Goto XDM Menu->Downloads->Stop Queue.

If you want to Schedule the Queue Processing at a specified time then Goto XDM Menu->Options->Scheduler. Check the Enable Scheduler option and specify the start and end date/time.