When you cook corned beef and cabbage in the slow cooker. Do you put the cabbage in at the beginning or towards the end.  ?

I too would cook the corned beef first, till its 'nearly' done. Lift it out add half the cabbage, put the beef back in, add the other half of the cabbage, then finish the cooking.

That’s precisely how it should be prepared. Too much water lessens taste, and placing the cabbage on top is preferable.

Soak the corned beef in cold water for a cupla hours, then cook in the crock on high for about 3 hours,with 3 cups water. Skim the fat off the top of the water, add the cabbage, reduce heat to low, and cook for 3 more hours.

If you are making it in the crockpot, you don't need water.  Just put everything in the slow cooker at the same time:  corned beef, cabbage, potatoes, carrots, etc) cover and cook on high for 4-6 hours or low for about 8 hours.  When I cook the corned beef over the stove, I add just enough water to cover it,and cook it for an hour or two, before adding the potatoes and carrots.  About an hour before it's done is when I add the cabbage since it cooks fairly fast

Towards the end. Let the meat cook a few hours before adding in the veggies, and then let them finish together.