Number of posts in slider

There are no options to change via admin
You have to change it in template via child theme

Thanks, and where exactly do I do that?

1) Download Leaf child theme from here and load it via FTP in theme folder
2) Copy home.php from original Leaf theme to your desktop
3) Open the file with an editor like notepad and change number 5 in these lines with what you want:

<?php
if ( ! isset( $options['leaf_slider_cat']) || $options['leaf_slider_cat'] == -1 ) {
$args = ( array( 'posts_per_page' => 5, 'post__not_in' => get_option( 'sticky_posts' ) ) );
} else {
$args = ( array( 'posts_per_page' => 5, 'category__in' => $options['leaf_slider_cat'], 'post__not_in' => get_option( 'sticky_posts' ) ) );
}
?>

4) Save and upload the file in child theme folder

5) I forgot something obvious: active child theme

Okay, will try – thanks for your time!