After downloading the style, upload the style folder, which you will find under the name shqawe-eid, to the styles folder in your forum home page.
Then upload the xml file from within the control panel.
There is an image named header-r.web without the site name to be used instead of the default image found when you unzip the folder, or you can download it from the attachments. After editing the image, upload it to the images folder inside the style folder.