Pretty much what
kraigwy has replied and would add that once you loosen the locking ring, Take a good initial look and then look away. Turn your rear bell 5-turns CW and take a look to see if it has improved. Go either CW or CCW in smaller turns, till you start seeing the desired results. There will be times when the verticle will be in focus and the horizontal will not. Just keep turning. Looking away between adjustments keeps the eye from trying to focus prematurely as there is a natural instinct to try a focus. ....
Be Safe !!!