Okay but would I do that in Cpanel or what? I don't understand ;n;

Nope, not in Cpanel, its in Admin Control Panel. You can access it from this link:

http://pewcats.mysidiahost.com/admincp/

I get it now! Thank you so much!

You are very welcome. Anyway you may try to explore the admin control panel a bit more, and you will be amazed at how much you can do with it. Enjoy. ^^

Aaaah I broke my themes trying to install the bookstore theme x.x Can you help me?

How did you try to install the theme? Did you go to the cPanel?

I moved the files like the instructions said and then I tried to use ACP and it didn't work
pewcats.mysidiahost.com

I checked your site and it seems that you uploaded the theme .zip file to folder /templates, but it is an archived file and you havent extracted it. Of course you break your site for this.

Sorry D:
What do I do to fix it? Get rid of the file?

Nope, you need to extract this file and then you should have a folder called 'bookstore', and it should contain some files such as header.tpl and template.tpl. You should upload this 'bookstore' folder to /template directory. What you did was to upload the .zip file, which will not work.