Choose a quiet location to record. The room should be as soundproof as possible. It isn't necessary to have a professional studio or a completely soundproof room, but a room that is not susceptible to noise intrusion will work best.
Open your audio recording software. There are many programs on the market, some free and some that range in cost from cheap to fairly expensive. Free software will do the trick, but choose software that allows you control over mixing as well as the ability to save in popular audio formats such as MPEG and WAV. Audacity is free audio recording software with excellent mixing and export features; it's available for PC and Mac.
Plug your microphone into your computer and position it on your desk in an easily reachable location. You want to be comfortable enough to record several paragraphs or pages at a time. You should not have to lean up to get to your microphone.
Go to "File" and Select "New." Begin reading from your manuscript or the book you want to record. Record a couple of samples to find the right speaking volume and to make sure you are enunciating words clearly. When you feel comfortable with your reading style, start a new file, introduce the book by title, along with the author's name, then begin reading. Keep your recording sessions down to a chapter at a time. Save each of the sessions as a separate file, which you can combine into a single file at the end of the session.
Go to "File" and choose the "Save" command. Save the book as an MPEG. This file can be burned on to CD-R discs so you can distribute your audio books.