Repeater is used in cases where you wish to repeat a task a given number of times. Let us assume you would like to send five emails with subjects "Hello 1", "Hello 2", ... "Hello 5". This could be accomplished with connecting Email > Send me and email module after the Repeater module:
With modules configured as follows:
You can imagine the Repeater module as a generator of bundles outputting one bundle after another. Each bundle contains one item named
i of type Number. The initial value of the
i item is specified in the Initial value field. The number of repetitions (= number of outputted bundles) is specified in the Repeats field. The value of the
i item is increased in each repetition by the value specified in the Step field, which is 1 by default (tick the Show advanced settings checkbox to reveal it).