Hi,
You can download following manual to understand these processes...It is for Small Business Edition but almost same things apply for Professional Edition as well...[Its a freeware]
USING MICROSOFT CRM 3.0 SMALL BUSINESS
http://download.microsoft.com/download/3/3/6/336CAAA0-29C4-4F44-A959-C45FEC98C7BF/CRM30_SB_Edition.pdf
If you want to go for some book which is not free then download
MS CRM 3 for Dummies
http://www.amazon.com/Microsoft-CRM-Dummies-Computer-Tech/dp/0471799459
you can also search on google, msn, yahoo with a title Special Edition using Microsoft CRM
Otherwise Quotes/invoices/orders processes are really easy...you can ask about your confusions step by step..