Yes there is an Object Model for FrameMaker. The most visible representation is in the ExtendScript Tool Kit's Object Model Viewer. You can access it from the ESTK help menu or by simply pressing F1.

There is also a PDF file with a great deal of essential FrameMaker information for all Objects, Properties and Methods. However before you get into FrameMaker scripting, you will need to get familiar with JavaScript programming because the core of ExtendScript is a rather elderly version of the popular scripting language. Again from the ESTK Help menu click on Adobe Intro To Scripting. The full detail is in JavaScript Tools Guide CC.
It may be that your FrameMaker installation does not include the ESTK. That can be downloaded as a free component of the Adobe Creative Cloud. https://helpx.adobe.com/creative-cloud/kb/creative-cloud-apps-download.html
Once you get started there's always help and encouragement on this forum. Enjoy your scripting!
Ian