I want to send respondents to 1 page if the answer the first question is “Yes”, but to the “Thank You” page if the answer is no. When I go to set up the logic, it only lets me choose a page number for one of the answers.
I am assuming that you are using skip logic (https://help.surveygizmo.com/help/set-up-skip-logic).
In the scenario you describe, our approach would be to skip the respondent to the “Thank You” page if the answer is NO. If they answer YES, the skip is ignored and the respondent moves on to the next page.
If you want to send your respondent to something other than the next page, you can create a second skip.