I set the frontpage layout on left-main-right. Modules on the left positions don't appear. I also tried left-right-main and it shows only right and main.

Dear Katarzyna Meszka,

We're sorry. This template hasn't "Left_top" and "left_bottom" positions. It has only "Left" position. You can add your module at "Left" position and enable on these menu item.

Thanks!

Thank you, now I understand. I haven't noticed it until now because I always looked at positions that are assigned to sj_worldnews and the left position is not (you can see it in the attached file).
Thanks for help!

Dear Katarzyna Meszka,

Please refer to demo.smartaddons.com/templates/joomla25/sj-worldnews/images/yt-positions.jpg

Thanks!