Excluding posts used for carousel slider from the Latest Post section on blog page

Pinegrow WP
2

Update
I found This Useful Answer from @Emmanuel on another post, which should make it work. However, after finding the post(s) ID (1018 to choose just one,) entering it into the Category section of Category Parameters and choosing ‘Not In’ from the Category Opts, the unwanted post(s) still show.

Screen Shot 2016-10-20 at 13.20.38.png303×782 36.2 KB

I’m unsure whether this should make any difference to ‘content-home.php,’ but it hasn’t. It has however added the relevant code to my ‘index.php.’

    <code> <?php
                        $cat_filter_args = array(
                            'category__not_in' => '1018'
                        )
                    ?>
                    <?php $cat_filter = new WP_Query( $cat_filter_args ); ?>
                    <?php if ( $cat_filter->have_posts() ) : ?>
                        <?php while ( $cat_filter->have_posts() ) : $cat_filter->the_post(); ?></code>

So, it really should be working. Again, any advice would be gratefully received.