Do you not really know the first thing about interactive fiction? That’s okay, because there’s lots of resources out there to help you begin.
There are different types of interactive fiction games, but in the IF world there are primarily two common types:
1) The choose-your-own-adventure story. These are also called gamebooks, hyperlink fiction, etc. the player advances the story by making choices from a list of options provided. Examples include the old CYOA books and the games at ChoiceOfGames.com.
2) The parser-based story. Instead of giving you the list of options, this type of game gives the player greater freedom. The reader types commands into a parser–the prompt for the reader–and the game responds in some way. Typical commands help the reader explore the world and gather inventory materials.
There are lots of resources out there to help beginners learn the world of interactive fiction. The Brass Lantern has a nice list of links to check out. There’s also some great tips at Ben’s Text Adventure Page (including this handy list of common commands to try in parser-based games).
Probably the best way to learn is by experimentation; here are some great games for beginners:
For CYOA-style games, check out the games at ChoiceOfGames.com: http://www.choiceofgames.com/category/our-games/
There are actually quite a few programs out there to write IF, and finding the right program is all about knowing what you want your story to be. I’d recommend checking out the Inky IF Guide to find out more about writing your own game.