When you click the Select Stations button on the Station Avails Quick Fill window, you'll see the Select Stations window and can select the stations for which avails are to be created.
To select all stations in the market, click the Select All 
button.
Use the Unselect All 
button to undo a Select All operation.
To choose specific stations, select the check box to the left of a station name to select it.
Click the Save button to save the selections and return to the Quick Fill window.
Click the Cancel button to return to the Quick Fill window without saving the selections.