This technique is simple enough for a new weaver to try it.
The pattern weft is either 3/2 cotton or embroidery floss ( all six strands at once).
The warp is threaded for a plain weave.
The pattern is 80 columns (160 threads) wide. There will be 20 threads on each side of the pattern to form a frame. Each dent (two threads) equals one block on the graph.
Weave the first shot of tabby.
With the shed closed, using a pick-up stick or small shuttle (I prefer the small shuttle) , run the shuttle under the background (white blocks in the grid) and over the black blocks. Remember to count two threads as a block. Once the thread is across the warp, then gently beat it into place.
Weave the next shot of tabby.
Continue to the next line of blocks on your design grid. Placing only one shot of tabby between the pattern shots. As you are working verify that you are getting 24 ppi. (counting the pattern shots)
If the inlay works out correctly it should be square. As you are going along, see if the shape is correct.
If it looks squashed (wider than long), then you are beating too closely or the pattern weft is too thin.
If the shape is longer than wide, then you are beating too loosely or the pattern weft is too thick.
Try changing the beat or the weft, do only one of the changes at a time until you get the combination just right.
The pattern weft will pack in pretty tightly, because of the width of the cloth and the fact that it is not a tabby interlacement.
If you think a float is too long for your taste you may pick up a background thread in the middle and not disturb the design.