Open Dreamweaver and go to the menu, Text. Click on it and go to CSS Styles and open New CSS Style....

This box will come up, select Redefine HTML Tag, make tag body and Define In: New Style Sheet File

Then this box will appear where it is possible to make a large number of different selections, beginning with Type

As can be seen here. Begin with just Type and see what it does. It is always possible to return to a Style Sheet and edit it, starting with CSS under Text.

Next the Style Sheet has to be included in the page - external Style Sheets are in most cases the most efficient way to work - and they can be Attached by going to CSS Styles again, under Text, and choosing Attach Style Sheet.

This box will appear and there are two options for adding: Link and Import. In this example, Import is used.

And the Style Sheet is linked to the document between the head tags.

This is what the external style sheet for these course pages looks like as an images. Here is text file of the same Style Sheet.