As the question says, im not clear on how to go about adding new input fields depending on values of certain fields in the form.

I got as far as setting a callback and a wrapper, but i just can’t seem to rebuild the form, i can do basic returns of values from the callback, but that’s about it.

If anyone could show me a clean, simple way where i could go from, that would be great!

<?php

//Create raffle form
function raffle_create_form($form, &$form_state)
{

    //Basic raffle info
    $form['raf_raffle_name'] = array(
        '#type' => "textfield",
        "#prefix" => "<h5>Raffle information</h5><hr>",
        "#title" => "Raffle Name:",
        "#required" => TRUE
    );

    $form['raf_allowed_number'] = array(
        '#type' => "textfield",
        "#title" => "Number of allowed members",
        "#required" => TRUE,
        '#element_validate' => array('element_validate_number')
    );

    $form['raf_start_now'] = array(
        "#type" => "checkbox",
        "#title" => "Start raffle now?"
    );

    $form['raf_end_date'] = array(
        "#type" => "date",
        "#title" => "When to close this raffle?",
        "#required" => TRUE
    );

    $form['raf_prize_type'] = array(
        '#type' => "select",
        "#options" => array('gift' => 'Steam Gift', 'hardware' => 'Gaming peripherals'),
        "#title" => "Prize type",
        "#ajax" => array(
            'callback' => 'raffle_create_form_type_steam',
            'wrapper' => 'steam_options',
        ),
    );


    if(isset($form_state['values']['raf_prize_type']))
    {
        $form['raf_steam_options'] = array(
            '#type' => 'textfield',
            '#title' => 'Added div',
            '#prefix' => '<div id="steam_options">',
            '#suffix' => '</div>'
        );
        $form['raf_steam_options']['#description'] = 'configure some steamy steam steam';
    }

    $form['raf_prize_name'] = array(
        '#type' => "textfield",
        "#title" => "Prize name",
        '#prefix' => '<div id="steam options"></div>',
    );

    $form['raf_prize_about'] = array(
        '#type' => "textarea",
        "#resizeable" => true,
        "#title" => "Prize description"
    );

    $form['raf_prize_thumb'] = array(
        '#type' => "file",
        "#title" => "Prize thumbnail"
    );

    $form['raf_prize_link'] = array(
        '#type' => 'textfield',
        '#title' => "Link to product"
    );

    $form['raf_raffle_create'] = array(
        '#type' => 'submit',
        '#value' => "Create Raffle",
    );

    $form['#submit'][] = 'raffle_create_form_submit';

    return $form;
}

function raffle_create_form_validate($form, &$form_state)
{

}

function raffle_create_form_submit($form, &$form_state)
{
    dsm('i printed');
}

function raffle_create_form_type_steam($form, &$form_state)
{
    dms('hi');
    return $form['raf_steam_options'];
}