connection between .evn and .cgrd in moving grid
 

Could anybody give me an idea what is the connection between a .evn file and a .cgrd file in moving grid?

I have read STARCD 3.26 manual a few times. However, I didn't get a clear understanding between these two files.

Is event file a file storing all the information of each event? And, is .cgrd file a file storing all the grid information of a mesh?