Have you tried Ultimate Category Excluder plugin? You can use it to exclude categories very easily. You just need to select the categories that you want to remove. It can be very useful, as you are not comfortable with coding.
Also, you can try using the following codes:
function exclude_category_home( $query ) {if ( $query->is_home ) {$query->set( 'cat', '-156, -58,-154,-155' );}return $query;}add_filter( 'pre_get_posts', 'exclude_category_home' );
You can find more information about the method of hiding category here.