Choose a Collection
Choose a target collection containing variations of the same mesh or completely unique ones.
Change the object seed value to further influence which object will be placed.
Select "Add New Array" to create an array. A straightened Bezier-Curve and a new Collection Object will be automatically generated, depending on your settings.
To make sure everything is working out of the box, the Objects inside the collection should be X-Aligned and Transforms should be applied.
PRO TIP: Use Blenders built in "Asset Browser" for organizing collection libraries and global access in every new project.