Weaving on a frame is a simple way to keep tension on warp threads. The frame can be any form, including a circle, square, triangle, or hexagon, or even a free-form shape, such as a tree branch.
What’s important is that the frame is rigid enough to keep the warp threads aligned and under tension. You can wrap the warp around the frame itself or around notches, nails, slits, pegs, pins, or even alligator clips that are on the frame. As you will see, keeping the warp taut enables you to pass the weft over and under the warp without tangling the threads.
Generally, the warp threads are evenly spaced between two sides of the frame. The number of threads per inch of space on the frame is referred to as the sett of the warp (sometimes also called ends per inch or epi). So if your warp is 10" wide and has 40 warp threads total, that would be a sett of 4, or 4 epi.
You may see a row of weft referred to as a pick or shot of weft. When weaving in the weft, it is up to you how tightly to beat, or push each row into place against the previous row. If you want to weave a fabric with a flowing drape, you will want to beat the weft rows somewhat loosely. If you are making a floor mat or any textile that needs to stand up to rough use, tightly beat the weft so the weave is dense. The density of the weft is called picks per inch, or ppi.
Have fun playing with the various techniques to see how the same yarns and techniques can produce very different results based on how close together or far apart your warp and weft threads are.