On the top left-hand side of the manual's page, click 
on the <span class="real_button">Browse</span> button and 
then select <span class="real_button">Advanced</span>. 
From the menu on the left-hand side of the new page 
click on the <span class="real_button">PDF Export</span> 
button. You can see now a hierarchical representation
of the manual's pages. Select the tickbox for the chapters or
pages that you want to export and click on the 
<span class="real_button">Export</span> button, at the 
top of the page. Once the process is completed 
click on the <span class="reference">here</span> link 
to view your PDF.</p>

What is a space?
A space is an area within Confluence, containing your wiki pages. You can think of each space as a sub-site, or mini-site, each with its own home page. You are looking at a space right now, called the Demonstration Space.

How many spaces should I create?
That depends on how you are planning to use Confluence. For example, if you are going to use Confluence for your intranet, you may want to create one space per department. If you want to use Confluence to write technical documentation, you could create one space per product.