How To Get The CSS Right For Adding A Sidebar To Baskerville[WP_Theme]?

I am working on the Baskerville theme right now, I am struggling to get the sidebar right. I have added the required <?php get_sidebar(); ?> in the index. And it’s visible now, but it’s below the entire area for posts, which I suppose is : content section-inner
What are the changes I should make to the relevant css below to have the side bar on the right side and not below everything?

.... .section-inner { max-width: 90%; width: 1400px; margin: 0 auto; }
.section-inner.content { width: 1440px; max-width: 92.6%; }

.section-inner.wide { width: 1240px; }
.section-inner.thin { width: 700px; }
.... .sidebar { width: 27.5%; background: #fff; box-shadow: 0 1px 4px rgba(0,0,0,0.1); -moz-box-shadow: 0 1px 4px rgba(0,0,0,0.1); -webkit-box-shadow: 0 1px 4px rgba(0,0,0,0.1); border-radius: 6px; -moz-border-radius: 6px; -webkit-border-radius: 6px; overflow: hidden; }

I would like to think I am pretty code savvy if just told what I have to do.

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