If you need to reset the skin(look and feel), log in as host, go to the Host>Skins menu and click the "restore default skin" link. If you really have to restore, click the Wizard link on the Common Tasks toolbar on the top right(logged in as host). Don't worry about the template, IMHO. It's not what you will ulitmately want. You'll be better off building your site and learning how to use DNN.
Try going to
http://www.traincert.net/register at the site, log in and download the free sample videos(left hand side after loggin in). Install & Config and the Product Overview should help.
Also try stepping through the help file from the beginning. Spending that time now will make you much more efficient at using DNN and ultimately save you a lot of time.
http://www.dotnetnuke.com/Default.aspx?tabid=787