Sitefinity 3.6 change template and theme

Hello. I am new to sitefinity.!
I have a site that is using sitefinity 3.6. I would like to change the template and the theme.
I am looking for a documentation that will guide me. Sitefinity's documentation  has information
only for earlier versions of sitefinity. 

Hi John,

In Sitefinity 3.6 you can also work with templates and themes as in a normal ASP.NET application. So you can lookup any masterpages and themes inside your source and change them.

If you have an account you still can download the 3.6 manuals. Let me know if you don't have them, because you maybe took over the project from someone else?

Kind regards,
Daniel