umka

Hi!
The plugin is designed to insert a <!--nextpage--> tag automatically. That’s all 🙂
Navigation through the pages should appear in the theme.
If it is not appear, maybe, your theme doesn’t support such navigation.
Check, if the following code doesn’t exists after <?php the_content(); ?> function call (‘single.php’ file):
<?php wp_link_pages( array( 'before' => '<div class="page-link">' . __( 'Pages:' ), 'after' => '</div>' ) ); ?>, you can add it manually. Also, this style should present in your ‘style.css’:

.page-link a:link,
.page-link a:visited {
	background: #f1f1f1;
	color: #333;
	font-weight: normal;
	padding: 0.5em 0.75em;
	text-decoration: none;
}
.page-link a {
	background: #d9e8f7;
}
.page-link a:active,
.page-link a:hover {
	color: #ff4b33;
}

I’ll add this instruction into readme.