In category item layout there is dropdown options called: select template!!
Where are the templates? can I donwload them anywhere??

Hi
you can define different template as per your contents requirement by copying some files. Please refer post k2community.joomlaworks.gr/notes/Templating_in_K2
After adding more template you will able to see more option in template select dropdown list. so you don't require to download anything from anywhere.
After reading post you will easily understand template selection functionality.

Please check the following as well...
k2community.joomlaworks.gr/forum/topics/templating-issues

The actual location to copy is:
/templates/yourtemplate/html/com_k2/templates/...