This blog is installed with the Protostar template.

You can edit the options in the Template Manager. Click on My Default Template (Protostar).

For example you can change the si background color, highlights color, site title, site description and title font used. 

Your site has some commonly used modules already preconfigured. These include:

• Image Module which holds the image beneath the menu. This is a Custom HTML module that you can edit to change the image.
• Blog Roll. which lets you link to other blogs. We've put in two examples, but you'll want to change them. When you are logged in, click on edit blog roll to update this.
• Most Read Posts which lists articles based on the number of times they have been read.
• Older Articles which lists out articles by month.
• Syndicate which allows your readers to read your posts in a news reader.

Each of these modules has many options which you can experiment with in the Module Manager in your site Administrator. Joomla! also includes many other modules you can incorporate in your site. As you develop your site you may want to add more module that you can find at the Joomla Extensions Directory.