To extract the files in the zip folder*:

Locate the compressed folder that you downloaded.

Right click on the folder and select the extract all option on the menu.

Select a suitable destination for the extracted files ( in this instance it is just on the C drive) and click Extract.

Open the extracted folder (refugetree) and double click the refugetree.htm file. The website will open in your browser.

*The screen shots here are how it appears in windows vista, please note it may appear differently on other operating systems