Collard greens are like gumbo, no two people fixes them alike. I look for younger, tenderer greens and I substitute chicken stock for water. Whatever I’m going to season them with (salt pork, smoked ham hocks, bacon, ham bone, etc.) I boil it in the chicken stock for two to three hours first. In the mean time, I wash the greens thoroughly (although they are a lot cleaner now than back-in-the-day).
Now, according to how you were raised, you can either cut the greens up with a knife, or you can tear them. Add them to the pot and cover. You may have to add gradually as they cook down. Boil over low heat until done. Taste the broth (pot likker) during cooking to determine if you need added salt, pepper, etc.
Note: For our family of five, I prepare four bunches. That guarantees us leftovers. Everyone knows greens are always better the net day!