The little icon ("Logo image") in the upper left corner of the desktop version spins. I'm wondering if there is a way to stop that from spinning and just have it be stable? I'm not sure if this a this-theme thing or just a general all-themes thing here but I thought I'd at least ask you. :) Thank you!

How do you make the sidebar appear on your theme and is there another way to make changes to landing page other than css? 

what is the easiest way of making changes to the the css, for someone who know little css and no oxwall?

The sidebar is a Oxwall component.  You will see it referenced in the master pages. There are also css  in the base css to display it alond with css in media queries to control mobile layout. You can reference the differences between simply responsive and simply responsive sb.  As for changing css, I recommend using inspect element to find the classes you need to change. I was like you, curious, but didn't know much about css. I used google a lot to help me. I learned  a good bit by just diving in. You will find some things difficult because Oxwall ties some things together, and changing one thing will change others that you don't want to.  These can be overcome by adding targeted css, or css that isn't already there to give the element it's own class.  Just as I did, it will start to click.