There are two types of logic you can incorporate into your surveys.
Maybe you have a survey where the first question on page 1 asks the gender of the respondent. Based on the gender you can then skip them forward in the survey to see only gender-specific questions.
Males would go to page 2 while females should go to page 3. Since males should not go to page 3, use page skip logic to end the survey after page 2 is completed by males.
Click the "Logic" tab in the builder. Select the answer you want to apply logic to and then select the page you wish to skip to.
If you wish to clear the logic out, simply click the "clear" button.
The best practice with this is to apply logic at the end of your setup. Keep in mind if you enable page randomization, unexpected survey behavior can take place.
If more than a trivial amount of logic is needed, we recommend writing down the logic on pen and paper first.