@louisebronn:
The screenshot is having the buttons from the addthis dashboard. If you are having an addthis account, you can enable the required share tool from the site dashboard. You will be asked to paste a code into your site page some thing like:
<!– Go to http://www.addthis.com/dashboard to customize your tools –>
<div class=”addthis_sharing_toolbox”></div>.
In the plugin’s settings page, select the custom button from Top Sharing Tool, and paste the above code into available text area. Also add your addthis profile id (AddThis Profile ID at top right of the settings page). Save the settings.
Please let us know if you are having any issues.