Font change

Hello my blog-in-progress is www.nowherelife.com. I am wanting to change the font used in the header and possible elsewhere.  I know I should be using the custom CSS and I tried to do so after looking at the tutorial.  Do you have an example snippet of code I would use?  Or is there another area on this site to find out?  I suspect this is probably covered elsewhere but I couldn't find it. Many thanks.