If you are new to CSAs, it is likely that tat soi and lemon balm are a bit unfamiliar. So, here is a bit of info on them as well as swiss chard, another CSA staple.
tat soi: a dark green Asian salad green that has a spoon like shape, a pleasant and sweet aroma flavor like a mild mustard flavor, similar to bok choi. Tatsoi is generally eaten raw, but may be added to soups or stir frys at the end of the cooking period.
lemon balm: a perennial herb from the mint family. This leafy green herb has lemon-scented, mint-like leaves that are often used dried to brew an aromatic tea. Its slightly tart flavor is used to flavor salads as well as meats and poultry.
swiss chard: a beet family vegetable with crinkly green leaves and celery like stalks. Stalks can very from a light silvery to deep red color.
braise, saute, steam. Swiss chard is used much like spinach, except that it has an appealing beet-like flavor and a heavier texture, which requires longer cooking. Many cooks simply saute it in olive oil and serve it as a side dish.