Login in to the website, using the same user as you are using in the Windows studio.

In the Windows studio, select "Save and test" from the "Test" menu. This then brings up the start new workflow wizard.
Fill in any two dates and then click next. The workflow is now started.

In the web interface, click "tasks" in the top bar. This will bring up a list of all current tasks assigned to this user. A new task will appear, asking you to approve your holiday.
Either approve or reject the request and the notification mail is sent to this user.