I understand, the "sample sites" that you have downloaded are basically some templates to create a WSS site. You should at least have WSS up and running and then install these templates. Now, if you create a site, it would ask you which Site Template you would like to use. You can choose the one you have installed and have the site. Essentially, these templates are used to create sites for specific use with a few clicks. For example, if you are interested in createing a Sales site, you must be looking for some sales related lists, a suitable look and feel, suitable webparts on your pages etc. Now, if you want to repeat the same thing for another site, you can create a template for Sales and simply use that template while creating the new site. Similarly, there are templates for HR etc. available on the Net. You may use these to quickly build your WSS site.