In the left hand menu bar on your 'my ebay' page, towards the bottom you will see 'manage my store'.
Click on that, and then go to 'holiday settings' also in the left hand menu.
Follow the prompts to set the dates you want and the message you want to display, and dont forget to 'turn it on'.
You can also choose to make your items not visible if you dont want any sales while you arent about.
