One place to start is by Googling "$app_name object model". The (full) help for most Microsoft applications includes this information, often disguised as instructions on use of Visual Basic for Applications or VBScript. These reference guides usually are not installed by default during the typical installation. They can be added later by rerunning the setup program with the custom install option. Also, one can often start the application in question, and select Tools/Macros/Visual Basic Editor, then View/$app Explorer, and the API should be within a click or two more.
You can also record a macro and then examine the code.
To record a macro
Use the following steps to record a macro:
To view a recorded macro
Use the following steps to view a recorded macro: