You might check out the templates for emails in the Business Productivity Kit. You might just set up fields at the top of your legal documents for name, address, date, and other information. Then write your text in below. You'll be doing some cut and paste of your current documents into FileMaker. After pasting in text command-z formats the text as your prescribe in FM. You'll be using the Slide-Printing menu item as well as document set up in Layout Setup > Printing for margins and so forth. You might also embed your variable information by making calculations with text output.
It would be a great investment to check out Lynda.com, FileMaker tutorial packages, and VTC I believe. I have a monthly subscription for Lynda.com and really find it useful. Just start in on the FileMaker 9 or 10 tutorials. It will teach you what you need to know. What you put into learning the ropes in this program you'll get back many times over. There are also books at Amazon.com.
I myself am a newbie and after learning from the tutorials have set up a contract solution for my business that has saved me hours of busy work. Type in the info once and I've got the contracts, envelopes, welcome letter, thank you letter, closing letter, etc... all at the press of a button.