I need help with my blogger post body width/margins/padding


I need help with my blogger template. I can’t figure out how to widen my post body (for larger pictures.text area) AND keep my sidebar the same size but also get that to scoot over a little bit, thus decreasing the margins around the blog…make sense? It always just gets moved to the bottom of my page. It’s all sorts of messed up and normally i’m pretty good at figuring it out myself but not this time. Help!