Hello mate,
I’m sorry for slow response.
To adding new block position, you must add below code snippet on layout definition files (.xml files in layout folder, you can edit them on admin panel > layouts tab).
<block name="topsl" type="spotlight" main-inner="1">user1,user2,user3,user4,user5</block>
type is name of file (without file extension ending) on blocks folder, so that If you want to add new block type, you must create new php file in blocks folder.
PS: You should edit files of your template folder rather than edit files on base themes folder.
you can read detail information at http://wiki.joomlart.com/wiki/JA_T3_Framework_2/Guides