The "Properties" box is typically located at the bottom of your screen (it varies in different versions of Dreamweaver). If you click on the "Format" box, the possibilities are:
- Header 1
- Header 2, etc.
Paragraph is normal (default) size; "Header 1" is the biggest type, and they get smaller as the numbers get larger.
You can also change the Font size using the "Size" box. In this case, 1 is the smallest, 7 the largest. +1 adds a little size, +7 the most; -1 detracts a little size, -7 detracts the most.
Default Fonts combine a number of font styles in each selection because not every browser will display the font the same way. If you really want to use a specific font, you have to use it by making a gif or jpeg file (using Fireworks or Adobe Acrobat) and then importing it as an image.