//form.html.twig
<form method="post" action="{{ path("createBook")}}">
    <input type="text" name="title" placeholder="title">
    <input type="text" name="description" placeholder="description">
    <input type="number" name="rating" placeholder="rating">
    <input type="submit">
</form>
//showAllBooks.html.twig
{% for item in allBooks %}
    <div>
        <a href="{{ path('showBook', {'id':item.id}) }}">
            {{ item.title }}
        </a>

        <a href="{{ path('removeBook', {'id':item.id}) }}">
            Usuń
        </a>
    </div>
{% endfor %}
//showBook.html.twig<div>
    {{ book.id }}<br>
    {{ book.title }}<br>
    {{ book.description }}<br>
</div>