No, you don't need to. Standuply takes a list of users from your Slack workspace. So if the person you want to add is a member of your Slack workspace, you just need to choose this person from the list in Respondents and Requests section of your report, that's all.
- Make sure you added team( if you didn't, click on "plus" sign and follow the instructions on screen):
2. Choose respondents in Respondents and Requests section of your report: