Here is how and where do enter the code:

First get code from a social bookmarking service like http://www.addthis.com/
Next add your code in CMS to Administer > Add Ons > Social Bookmarking & Sharing:
Next update your template. You will need to insert the code below into the template where you want your social bookmarking tool to show up:

<kintera:quicklinks>
<kintera:SocialShare />
</kintera:quicklinks>

Finally, enable it on the web feature yu want to see it on.

Keep in mind that currently there is only one box for code under Administer > Add Ons > Social Bookmarking & Sharing:. Add the secure version of the code to the secure box and Sphere will display the correct one.