To Construct a Rectangular Array of a Feature

Select the Array Feature tool.
Set Array Type to Rectangular.
Adjust other settings as required.
Select the feature.
The array displays dynamically.
Enter a data point to accept the array.

Left: Select the feature (1) and the array positions display. Accept (2) to complete the array. | Right: The completed array.

Where the topology of the model varies, the Identical Instances setting controls how the array is created: Left: On — array items are placed only where the topology is identical to the original. | Right: Off — array items are placed even where the topology varies.