1. Define a view for your report in reports/book_loan_templates.xml:

<?xml version="1.0" encoding="utf-8"?>
<odoo>
<template id="my_module.book_loans_template">
  <t t-call="web.html_container">
  <t t-foreach="docs" t-as="doc">
  <t t-call="web.internal_layout">
    <div class="page">
      <div class="oe_structure">
        <h1>Book Loans for <t t-esc="doc.name"/></h1>
        <table class="table table-condensed">
          <thead>
            <tr><th>Title</th><th>Expected return date</th></tr>
          </thead>
          <tbody>
            <tr t-foreach="doc.loan_ids" t-as="loan" >
              <td><t t-esc="loan.book_id.name" /></td>
              <td><t t-esc="loan.expected_return_date" /></td>
            </tr>
          </tbody>
        </table>
      </div>
    </div>
  </t>
  </t>
  </t>
</template>
</odoo>

2. Use this view in a report tag in reports/book_loan_report.xml:

<?xml version="1.0" encoding="utf-8"?>
<odoo>
  <report id="report_book_loans"
          name="my_module.book_loans_template"
          model="library.member"
          string="Book Loans"
          report_type="qweb-pdf" />
</odoo>

3. Add both files in the manifest of the addon:

{
    'name': 'Chapter 13 code for the qweb report recipe',
    'depends': ['mail'],
    'data': [
        'views/library_book.xml',
        'views/library_member.xml',
        'reports/book_loan_report.xml',
        'reports/book_loan_report_template.xml',
    ],
    'demo': ['demo/demo.xml'],
}

Now, when opening a library member form view or when selecting members in the list view, you should be offered to print the book loans.