Sidebar help

‘m using the boilerplate theme, and I have a page i created i have just one sentence on it, and i’m using the default page style. I think it includes a side-bar, when I add a widget to the sidebar it shows up on the page, but what I don’t understand is why the side bar is taking up the entire width of the page, and the title of the page and the sentence I added are showing above the sidebar (or what I think is the side bar…. here’s a link https://mdala.org/development/test/

I’m new to PHP and WordPress so I’m really having a tough time trying to figure out how this is working. Any help in pointing me in the right direction would be great appreciated. Thanks.