...You need MS-Access if you want to work with the program code (part of Office 365).
The program processes Invoicing, Appointments, and Quotes, and produces reports for A/R, Inventory, History and Accounting Purposes.
See the readme file, and manual for greatest use of this App.
Find other free programs at: https://gotomarcus.com/marcusacademy/marcusmain/index.php