If you want the variety maps in the combine monitor, I'd download the free trial of SMS and watch the video(s) on importing and exporting variety tracking. 

But that's IF you want to see the variety maps with your eyes on the screen. 

If you just want the yield x variety info after harvest is over you don't need to do any of those steps. Just import both the planting and harvest data into SMS or Operations Center (free) and in either one you can find yield of the different varieties since you have both layers.