You should look at what you want to produce before you start to convert the text. There are a variety of elements that may require tagging in the text portion of a multimedia application:
Character attributes. These are the codes that indicate bold or italic type styles, character fonts, color, inverse video, etc.
Hierarchy. The document hierarchy is its basic structure. This is usually expressed in book terms, and includes such hierarchical elements as title; chapter heads; and first, second and third level heads.
Links. These are the hypermedia elements that you click to initiate some action, such as jumping to another location, displaying a picture, or playing audio. Links are the most difficult element to automatically add to a file.
Define these and other elements of your target text before beginning the conversion process.