When you sign up, your dealer's Price Book will be automatically integrated into the system and will automatically sync price updates on your behalf, which can be visible when you build a Quote or associate a quote with an Estimate.
You will want to have all your services and other items in the system to create complete estimates and invoices. This is where additional Price Books come in.
Unlike the integrated price book, these Internal Price Books will be manually created and maintained by you or a member of your team. Examples of additional Price Books include
Warranty Price Book
Services Price Book