How to Configure W3 Total Cache

I am trying to speed up my site: http://londonard.com/ and have installed W3 Total Cache plugin, but I am struggling to get the settings right. I have tried to follow these instructions: http://publishingwithwordpress.com/installing-w3-total-cache-plugin, but it seems to involve setting/installing a whole bunch of other stuff: Varnish, APC, Apache, CDN…

I have to say, I find it all a bit confusing, as you can very well understand I’m a bit of a newbie! Could someone talk me through how to set this up please? At least the few simple “musts” that I should get right. Many thanks!