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To create a predictive dialer, you need to go to the Queues page of the Admin application. You can create a new queue on this page by clicking the Add button and selecting the predictive dialer (Fig. 1). Clicking the Create button opens the General page.
Fig. 1. Modal window "New queue"
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Open the Members page for this queue - click the 
button 
button for the selected queue.
More details about adding or setting up members can be found here.