An example of a (complex) array is the email attachment. The module Watch emails returns an array of attachments for every email. Every attachment represents a collection that may contain a name, content, size, and the like.
To add a new item to an array, click the button located in the target field (e.g. Add an attachment button for an email). This will bring up a panel for entering the item. The panel allows to map fields in the same way as with any other type of item. This way you can add any number of items to an array.
If you do not want to fill in each item separately, but want to map another array into the target field, use the Map button. In this case, make sure that both arrays (the source array and the target array) have the same structure.
Arrays can be divided into individual bundles using an iterator.