The default skins and templates have karma votes disabled (better: left out). Here's how to add them to your template.

1. Open the template for the main index

Start editing the template named 'default' (when starting from the default skins/templates that come with Nucleus)

2. Edit the 'Item body' template-part

Edit the bottom part of the item body templatepart to be as follows:

<div class="iteminfo">
  <%time%> -
  <a href="<%authorlink%>"><%author%></a> -
  karma: <%karma%>
    [<a href="<%karmaposlink%>">+</a>/<a href="<%karmaneglink%>">-</a>] -
  <%edit%>
  <%comments%>
</div>

On the main page, the iteminfo line for the items will now look like:

3. Template for the detailed pages

At this time, the karma score is only listed on the main page. To make it appear on the detailed page also, the same change needs to be applied to the template with name 'detailed'