This answers WHY they evolved, not how. I'd really like to know how they evolved, as in what began the process to make them carnivorous, and what the intermediate forms would possibly be.

You'll never get concrete answers to HOW venus flytraps (or people) evolved. You'll get guesses, theories and people who state guesses and theories as IF they are facts, but there is no proof for evolution. Intelligent Design is also a theory, but it takes far less faith to believe a superior intelligent being created venus flytraps (and you and me), than the gargantuan amount of faith you need to believe that due to poor soil conditions, over time, these plants managed to morph into meat-eaters. (And primordial goop turned into you and me.) Put another of your plants into poor soil and see if, over time, it makes itself carniverous. I'm really impressed by your persistance in getting the exact answer to the question you asked. You are shrewd. Keep looking for answers and not letting people side-step your questions. You have the determination to discover the truth yourself.