When you are building a squeeze page, you generally will not specify a time before the registration popup shows, but rather how many listings your potential lead can view before we prompt them to register.
This setting only applies to squeeze pages, not your K+ site. The website itself has built in triggers for when to show the registration page to new website visitors. When to display the prompt to sign up has been tested over many years, and our current configuration has the best results. For squeeze pages, showing the registration prompt right away is best. But, you can experiment with the values here, if you want to run two advertising campaigns side-by-side to see which one gives you the most leads, we encourage you to do so.