How to change site title width (instructions for a newbie please)

I read this (resolved) post about how to change the site title width so that it spans the whole width of the page (after having taken out the search bar) – https://www.ads-software.com/support/topic/changing-site-title-width-in-twentyeleven?replies=10 . Right now, my site title breaks into 2 lines and spans only half of the page width. Same goes for my tagline.

Being a newbie, I have to admit that the answer given in the above post is still too technical for me and I don’t quite know how to do what it says should be done. May I ask if someone could please post instructions for a newbie like me? I’m using the TwentyEleven theme.