Hi Hchauhan,
Based on the error you listed, it sounds like you haven't installed the Team Coding objects into the database yet. Those need to be installed if you want to control database objects within Team Coding. Without them, all you'd be able to do is file/script-based source control, in which you'd need to handle everything manually.
I would recommend reading through "Getting Started with Team Coding" document, which can be found here:
That should help walk you through installing the necessary Team Coding objects, as well as linking to your VCS and configuring a basic project to control desired database objects. The PDF is written for Toad 12.9, but you should also be able to use it with Toad 12.12. If you have any additional questions, please feel free to post a response on here and we'll do what we can do help.
Thanks,
-John