Loincloth is fabric covering your genitals and ass. How to put on one-piece loincloth can be found on wikihow (with images!). You can also have much simpler variant or short-skirt design. There is also Skirt Loin Cloth option. (Links are to Etsy.com because it is easy to find examples.) As material, I am not sure whenever use hemp fabric (or other simple brown fabric) or fur. For design, I like the skirt-like design with cut on sides.