For example, if you bring up help for WMIC at the command prompt, it shows various aliases available for management.
Each alias is associated with a WMI class. You can find an association by using alias command at WMIC prompt.
<Alias> /?, for example COMPUTERSYSTEM /? will provide help on how that object can be used to get/set information. Similarly, you can use the help option to see understand each option available. This is a standard set of options for all objects within WMIC. CALL option within this list if something interesting. If you check for help on this, you will actually see a list of all methods available under this WMI class.
This provides a great way to learn about WMI classes and method. You can also correlate this to Win32_ComputerSystem documentation available on MSDN website.