What is an array (also referred to as a sub-panel, palette, etc)?
An array is putting multiple pieces of the same part number into frame to make small boards more manufacturable for fabrication and also to reduce assembly costs for small boards. To configure your design to be in an array, go to Settings>PCB Configuration and go to the Production Page of that wizard. Click on the Array Checkbox in the middle of the page to open the array options for editing.