I completely don't know how to use s2. Where i can find this ?

Go to this page:

http://www.livejournal.com/customize/switch_system.bml

And make sure that if you're still using S1, you switch to S2, or if you're using S2 don't make any changes.

You should then be able to find the layout styles by going to http://www.livejournal.com/customize/ and changing the "layout" fields to match the instructions.