You can end your pulse in two different ways.
Set a pulse end date when creating a pulse
You can choose an end date for your pulse survey when you set up your pulse campaign. This is the last step in the process! It's optional, so if you aren't sure when you want your pulse survey to end you can leave it out and manually end your survey instead (see below).
Manually end your pulse survey when it suits you
To do this find your live survey in the 'your campaigns' list. Using the dropdown on the right-hand side click the 'End' button. This will instantly end your pulse survey and close it to responses.