Categories as selectable links on submission form

Once you retrieved your categories, let’s say in $categories, you can do something like this:

<?php
foreach ($categories as $catgory) {
    ?>
    <form id="cat-button-form-<?php echo $category->ID; ?>" action="<?php echo $url_to_step_2; ?>" method="POST">
        <input type="hidden" name="mycat" value="<?php echo $category->ID; ?>" />
        <input type="submit" name="getcat" id="getcat_<?php echo $category->ID; ?>" class="btn_catstep" value="<?php printf(__('Select %s &amp; Continue'), $category->name); ?>" />
    </form>
    <?php
}
?>

In step 2 you then read $_POST['mycat'] and go from there.