Learn online. When you search online for accounting system tutorials, you will get plenty. Take a look at them, including costs and the specific topic you want to learn. Ask an Internet accounting group, such as Accountants World, about options regarding online tutorials You can search the Internet for "accounting discussion forum" or "accounting listserv" and get in touch with accountants who can give you opinions about learning online.
When making your selection, ascertain that the tutorial is based on the same program version as the one you want--software may change dramatically from one version to the next.
Consider the tutorial that may be available as part of your software, especially if you have some knowledge of accounting. Usually it comes in the form of a video that runs on your computer, or on a website, and can be really great tools to learn accounting. Intuit offers this tutorial service for its QuickBooks software.
Many times programs have such a good help function that it can be considered a tutorial. Each screen you navigate may have its own help menu, specific for that page. You could also do a search on the help menu and get very detailed information on how to perform certain tasks.
Buy a book that is a tutorial. You can find book tutorials in popular programs that can be very useful and easy to follow and learn with screen shots of the software and case examples. These books often include CDs with data for exercises and illustrations. If you're patient and prefer learning from paper books, this a good option to study and master accounting programs.