Do Your Homework Review a few of the directories before you start. Get a feel for how they list programs. All provide a 'drill down' category selection and some also offer a keyword search. Look at the category choices to find the most suitable to submit your program to. Try to search as an affiliate might.
Some headings can have more than one meaning.
Finally, I suggest avoiding the 2-tier category if you're only allowed one category choice. Next plan out the data you want to submit. I suggest when your asked for your URL if you're only given the option to provide one address submit that of your affiliate information page. You will also need a list of keywords or key phrases, comma separated. An editor reviews all submissions.