This diagram is of a backstrap loom. To create woven fabrics on a loom, one set of yarns (called warp yarns) is held relatively taught vertically between the loom bars. On this loom, the top loom bar would be attached to a tree or pole, and the weaver would sit facing the loom, legs out in front with the backstrap around the lower back. Therefore the tension of these yarns is controlled by the weavers body. Also the fact that this loom is not staked down like other types of looms makes it portable.
The heading string and lease cord are used to create a warp selvage (or clean uncut edge of fabric that won't unravel). The shed rod and heddle both keep the warp yarns separated into 2 groups (every other yarn). The heddle has individual yarn loops, each one looping around an individual yarn from one of these halves of the warp yarns. When the heddle is lifted (as is the case in the diagram) the 2 groups of warp yarns separate, leaving a space known as the shed. A second set of yarns run horizontally and are inserted into this shed, these are known as weft yarns.
Weaving process: The heddle is lifted, one weft yarn is inserted into the shed, then the batten/sword is used to beat that weft yarn as close to the resulting fabric as possible. Then the other half, or some other carefully picked out combination of warp yarns, are lifted to create a new shed, and the next weft yarn is inserted. Fabrics created on this loom are always woven to a width no larger than the arm span of the weaver.
A major goal in this project is to animate the weaving process, maybe starting with a simple fabric structure. It would be nice to be able to zoom in and show the precise process, hand motions, and tools in use. I will be posting an image shortly of some illustrated fabric structures, I will try to keep it concise sorry this was so long!