I'm quite new to Joomla and web design in general. I'm working on the website for my elementary school and I need to figure out how to change the design, color of the background and whatnot. If anybody could point me in the right directions I would be most appreciative.

I think you're looking for a template. There are many available to shop for. That's the simplest way to change the look of your site, and you get a consistent treatment/styling on all your content and pages. If you want a custom template or want to adjust the look yourself, unless you want to go through a quite a learning curve, you can hire a Joomla designer.

Here's a basic introduction to templates: docs.joomla.org/Tutorial:Introduction_to_Joomla!_templates

Here are some Template shops:
www.rockettheme.com/joomla-templates
www.joomshaper.com/joomla/free-templates
www.joomlart.com/joomla/templates/showcase

Hope that helps. :)

Here's another shop: www.templatetuning.com

I recently took this one: www.templatetuning.com/joomla-templates-preview/38083.html

...and am building a site with a client with it.

Here's where we are so far: www.asp247.com