This is legagy system that is written for Unix and DOS, but actually now only works under Windows (32bit or 64bit using DOSBox). It even installs like a Windows program, but email for help if you need it ballweiss55@gmail.com
PBAS is for more general Service and Inventory businesses, and is feature filled. Download the program you like, and a manual is accessed by pressing F1 from the main screen.
For Educational use, learn how to setup the Chart of Accounts, read Financial Statements...