This action creates a repeat loop together with the Next action.
The Repeat action marks the start of the repeat loop. In a subsequent step, another iteration of the loop can be requested using a Next action. The windows, pages, etc. at the Next step will be sent back to the Repeat step and will become the output from the Repeat step in the next iteration. If no Next step is executed in a given iteration, that iteration will be the last one, and the repeat loop will end.
The Repeat action is particularly useful for looping through pages that are connected with next-page links, like this:
See Pages where Each Page Links to Next for examples on how to use the Repeat action.
Following is a video giving an introduction to using the Repeat and Next steps.