there’s more to it than that, W3Total Cache is a full featured and complex plugin – on the plus side it is extremely powerful and on the down side, you can break your site or make it slower if you don’t know what you’re doing
> What settings should be set then..?
it really depends. for example, are you using vps? or shared hosting? etc.
there are lots of tutorials floating around but most are out of date, this one is probably the most recent and complete:
http://code.tutsplus.com/series/configuring-w3-total-cache–cms-656
