When you're done, you can click on the 'Close' tab on the floating bar. The items in the header and footer will appear greyed out, but don't worry; this only means the they have been set. The cursor will then appear on the first line where you can begin typing your letter.
What's format? _ This is the layout of your document, where you decide the key order of the components (or chapters) of your standard. So for a user guide this might be; Contents Page, Product Introduction, Product Photo, Full User Guide, Quick Reference Guide, Copyright Statement, and Disclaimer. You can add as much or as little detail to each section as you feel necessary.