Hi Phil

Get hold of the Doepfer manual, there's hours of entertainment and so many indispensible modules and valuable ideas listed.
If you get one book, get the one by Allen Strange. it is out of print and horribly expensive, but you can access an online copy for $15 from McGraw Hill here https://ebooks.primisonline.com/eBookstore/index.jsp

Cheers, and have fun, Nick