Whatever Theme you choose make sure it is fully responsive. A responsive theme can be viewed in any view port which means it will automatically adapt to the size of any mobile device, such as iPad, iPhone, etc.
Here is a good video showing you how to install your WordPress site within the Hostgator cPanel using Quick Install.
Then installing the “Responsive” free theme, adding pages, changing the homepage, adding your own logo, plugins and widgets.
To create your logo for free go to http://pixlr.com
Before installing your theme take the time to read the “read me” file that comes packed with most themes. Usually the theme developer suggests what plugins if any to install. The read me file can be found by going to the “File Manager” within your cPanel, then select the wp_content folder, then the Themes folder, then select and open your theme’s files and go to the read me file.
Also it is highly recommended to create a child theme. You can learn all about child themes at: http://codex.wordpress.org/Child_Themes