change default font family

Hi-

New user to CK here, and I am definitely not a Java Script programmer! I need to be able to change the default font in the editor. My client uses only one font for their site, although there are variations such as bold and different sizes. I've tried everything I understand, and can't get it to work. Most of the directions that would seem to work are beyond my level of programming skill. Anyone know an easy way to do this? If not, is there anyone I can hire to do this for me???

ARGHHHH

Thanks.

Don