Get the pixel coordinate of the particular image or object with respect to color

I don't know about searching for a particular color.  However, you could probably adapt FindRegion (https://support.smartbear.com/testcomplete/docs/reference/project-objects/items/stores/regions/findregion.html) to search for the red square in the larger image.   That will return a "Rect" object. https://support.smartbear.com/testcomplete/docs/reference/program-objects/rect/index.html

Using the properties of the "Rect" object, you can probably adapt code to click on a set of co-ordinates based upon the Top and Left values.