Start at finding CCB to COB. Now start moving slightly until you get your first clear visual of CTE. Check to see if you also have ETA or C. If it is a B, keep moving to the next clear CTE. Check to see if you got ETB.
This gets easier and easier in my own experience. Obviously, it's real easy 99% of the time for Stan, Stevie, Landon, Gerry and mohrt as can be seen by watching the videos. I still get sme I just can't pick up for whatever the reason. In some cases, I've just stepped completely away and come back changing body position and perhaps, distance from the CB. After the last lesson from Stan, I learned to also try to find 1/4, 1/2 or 3/4 overlap as the starting point and then fine tune from there. One other thing I found was I previously was too closed in my alignment. I'm speculating this was causing some conflict with dominant and non dominant eye. Opening up my alignment when acquiring my visual seems to allow me to see it better. Thin cuts to the right are a challenge to me in particular and Stan helped me figure out it was the eye conflict that was screwing me up on thin cuts period. Practice has helped that but I have to focus more on these to get it right.
If you didn't get it with the DVD, download the proposition shot diagram mohrt put together and is on his website. His website is chock full of helpful information, he's done an incredible job with it.