If you are unfamiliar with CSS, you might want to do a search on the internet for a CSS primer and get yourself familiar with it in general. There are great primers out there and that is how I am learning. No need to repeat what they can say better.
WA has a good CSS editor - to answer your specific question, open the editor and add the following in an appropriate place in your CSS (which may just be a blank screen if you have not done any CSS customizations . . . )
#idPrimaryContentBlock1Content H1.pageTitle
{
font-family: comicsans;
}
HOWEVER - I can't recommend using a specialty font in a website. Only people that happen to have that font installed on their PC will see it on their webpage - rest of people will see the default font, which if you have not detailed in your CSS will default to whatever the browser defaults to I think.
Arial and Verdana are pretty "safe" bets for web pages. A lot of sites that you see specialty fonts on, the text you are seeing is actually an image.