hi Frank,

you re almost there, pls hang on...
you re right to download the taglist template from Download section.

The "template" term here is not referring to Joomla template, but it is referring to YouCMSAndBlog taglist "template" definition.
You can get more full understanding about their terminology by by reading this tutorial about how can you create a new YouCMSAndBlog taglist template. In other words, you can create new taglist template for not only Joomla, but others open source & commercial CMS.

Okay, now back to your problem:
1. Dont modify downloaded joomla15.taglist.xml to joomla.taglist.xml since joomla.taglist.xml (shipped together with YouCMSAndBLog zip file) is for Joomla 1.0.x and has been configured inside configuration.xml. As for now, pls restore back the original one

2. Open joomla15.taglist.xml (the one you have downloaded from Download section) with any text editor.

3. Read line #3 about how you can install this taglist template by modifying configuration.xml (which is by copying entire block of <editor/> starting from Line #5)

This taglist template was a great work with good comment inside created by Luc Wuyts ...sigh he dont leave any trace or email address so cant credit back to him

Hope you have clearer picture now.