Stereo calibration, how to use E and F matrix for transform image to an another image coordinate system

Hey hi all, I have a question in stereo calibration. I am using IR camera and RGB camera. I have used the standard method of stereo calibration and found all the parameters. But, after undistortion and rectification, I wanna overlap one image onto the other. How would one achieve this, after knowing all the parameters. Please help me. I am completely new to stereo vision. It would be of great help, if someone could shed some light on my question.

I would like to keep RGB camera as a reference. And have IR camera image to be transferred to RGB frame. So that, for every point in RGB image, I would have an additional temperature information in RGB image.

Like a thermal map over a RGB map. But, right now, it is displaced. But, I had done stereo calibration, and have all these parameters, like essential matrix and fundamental matrix. But, I am not sure how to exactly use it to achieve my intended result

Please let me know if my question is not clear
Thank you