Firstly, simmer the garlic in enough olive oil to cover them comfortably in a small pan, simmer these for half an hour on the lowest setting or until the garlic is soft and tender, you can use less if you like. When they are soft roughly chop them and reserve the garlic oil.
Then while this is happening, prepare the mussels. I buy 2 dozen to allow for some that may not open after steaming. They should feel heavyish before cooking, gently pull the weed or beard away from the mussel and rinse under a slow trickle of running water, I tap them on the sink to close them if they are open and make sure they are alive. When this is done place them in a colander to allow to drain.
Slice your bread into generous sized peices to slurp up the tomato juice, then sprinkle with olive oil and cook in an oven on 180 degrees for around 10-15min, about the time to cook your dish.
Put the garlic oil and garlic in a large saucepan or wok on a medium to high heat and cook for 1min, then add your tomatoes and season, warm through then add your mussels and wine and put a lid on the pan until the mussels open (3min roughly) then pour the lot into a serving dish and garnish with the herbs. Discard any mussels that do not open or are cracked. Serve with the bread.