I'm going to be really basic in this explanation of weaving, but I think it'll make things a little clearer.
Weaving is simply, over under over under over under, right across the stretched out cords, those are the warps.
The alternate row, under over under over under over, weaving the weft through back to the start.
All a loom does is lift all the overs up so that they are seperated from the unders to create a 'shed' space for the weft.
Then, the most important bit, it creates the opposite so that the unders become the overs and creates the alternative shed.
That loom in the illustration does this by having one set of fixed warps and the second set that can either be lifted above those to create the first shed, or dropped below them to create the second shed.
The shed is the triangular space created at the weaving edge where the warp threads or cords pass each other.
That bushloom makes for simple mats, pads and hangings, but since it's edges aren't selvedged (think weft woven back and forwards) they will always be too easily slipped to make something very flexible unless the warps are very, very tight.
Have a play with twine and paper and you'll see it all come together easily.
I found the best mats I made from it were ones that I used twisted grass rope as the weft and rush cordage as the warps.
If you use plastic bags for both it makes good waterproof bootmats for tent doorways. Practical recycling
cheers,
M