Cut chard where the base of the leaf meets the stem. Set leaves aside.
Trim the cut ends from the stalks and cut stalks into small pieces. Set aside.
Stack a few chard leaves and roll tightly. Slice rolled leaves into strips. Repeat with the remaining leaves.
Wash and dry the cut leaves and stalks.
Add oil to a sauté pan over medium heat. Add a couple handfuls of greens and cook until bright green and wilted. Add garlic and stir well, then add the remaining greens a handful at a time until all greens are wilted and bright green.