Here's how you do it:
If it's a Sony lrf file, go to this thread:
https://www.mobileread.com/forums/forumdisplay.php?f=126
That thread is the upload section for the Sony books - the lrf format.
Find the phrase, "
NEW THREAD" - unfortunately, that phrase is very small, but it's right above the larger phrase, "Threads in Forum."
Click on "
NEW THREAD," and you'll be presented with a small window area to put in some introductory words - you know, words to the effect that you are the author, any copyright information (for clarification), etc., etc.
Here's an example of a book I assembled and uploaded, in order to give you an idea of how it should look look:
Dunsany, Lord: The King Of Elfland's Daughter. v1. 16 Jan 09
Then, to the right of that, find your genre.
Remember, this is for the LRF book.
In order to do the mobi/prc, you unfortunately have to repeat the same process.
If you have any problems or questions, you can post to this thread or pm me.
Don