Right before you cook the mussels. Rinse them in cold water. If the shell is open, tap on the shell to close before steaming. Check to see if the mussels need to be debeard. This looks like a little tag on the side of the shell. Firmly tug the beard out.
Add the broth and wine to a saucepan:
In a medium-sized saucepan add the chicken broth and white wine. Bring to a simmer and let the alcohol cook out.
Add the mussels:
Add the mussels to the boiling water and cover to let steam. Cook for 5 minutes. Remove the lid and check to see if the mussels have opened. If they have not yet opened add the lid back and cook for another minute. Discard the mussels with the shells that have not opened by now.