Learn C++ COM - Books, practical examples, your own thoughts

What are the pre-requisites to learn C++ COM? From where and how to learn it?

Got hold of few websites but it all sounds greek to me.

Goal: Develop an application that would interact with a RTD server then pass the variable to some control of another application. Kind of similar to Excel's =RTD() function, but, in my case it would be a different application instead of Excel.

Limitations: My knowledge in C++ is limited to high-school level academics only. But I am a true programming enthusiast.

Your guidance would immensely help! Many thanks!