My blog is broken

In case you haven't noticed my blog is broken. I did it, I admit it. I deleted something in the HTML, at least I think that's when it happened. Problem with deleting HTML is that I have no idea what it said or meant in the first place and no way of undoing whatever it is that I've done. So, if there is anyone out there who speaks computer or who is just better at blogger than I am...PLEASE HELP me get my sidebar back on the side where it belongs.