I have brought a couple of videos on simple warp float technique over here from my Flickr page which show how to weave the lower of the two triangles at left.
There is a full tutorial on this technique on this page. These videos supplement those instructions.
In the videos I am weaving the triangle shown above and show how to float the first three pairs of warps – pairs 1, 3 and 5. The second part of the video shows how to float the second set of warps – pairs 2 and 4.