Keystroke: m for Layout menu
This menu contains many codes related to formatting and translation in Nemeth Mathematics notation. Details regarding the use of these codes are given in the Topical How-To Guide, a DBT document which is typically installed as C:\Program Files\Duxbury\Duxbury 10.6\Documentation (English)\dochow.dxp.
Unless you are an experienced math braillist, you may prefer the "easy way out", and use Scientific Notebook to prepare your mathematical material, and import the resultant file into DBT. For more details click here: Miscellaneous: Scientific Notebook.