Place your mouse over the question that will determine where your respondent should be taken and click on the Add Logic button. A new window will appear that lists the answer choices and a drop-down box beneath each one. The drop-down box will contain each of the questions that are placed after the selected question. There is also the option to end the survey if the respondent selects this answer. For each possible answer, select which question the survey should go to. Once you are happy with your selections, click the Save button. 

NOTE: On the Survey/Form Settings step the "Show survey/form on a single page." checkbox must be unchecked in order to utilize logic with your questions.