Which variable to use to dynamically redirect survey respondent upon completion

Which variable to use to dynamically redirect survey respondent upon completion

Hi there. I am using another platform (Recollective) to send out a Zoho survey, and need to dynamically redirect respondents back to the platform upon completion, such that their response is logged as being completed as an activity. I am following these instructions to do this: https://helpdesk.recollective.com/article/120-linking-to-external-surveys. I would like to know what variable I should use at the Zoho end to do this i.e. in these instructions above, the variable is onComplete but it indicates that this will change depending on the survey platform. Appreciate any help, as I am getting confused! Thanks