In Respondent.io, how to get referral codes for studies I screened for a few days ago?

I screened for a study in respondent.io the other day, and want to share a referral code with a friend, but I can't figure out how to get to it. It won't let me take the screener again, and the code isn't on my list of past projects. Is there a way to get back to it, or was I supposed to copy and save it when they first showed it to me at the end of my screener?