When you dress, you put your clothes on. A dress is also a kind of one-piece shirt and skirt combo that can be fancy or plain. You can also dress a salad with salad dressing!
When you’re putting your clothes on, it’s usually phrased “get dressed.” If you dress up, you’re putting on something special. You can also dress another person — you might dress a toddler in a snowsuit or dress your dog in a sweater. When you dress a turkey for Thanksgiving, you don't clothe it, you simply prepare it for cooking. This is the oldest meaning of dress, which comes from the Old French dresser, "prepare, arrange, set a table, serve food."