I don't have any photographs of me doing this craft at the moment. I'd have to get some more bottles to make a tuturiol like that. I will try and explain, but if you don't understand then I'll have to wait for 2 more bottles to actually show you
1.Make the bags into one continuous strip. There's tuturiols online for making bag yarn that can help if you don't know how to do that.
2.Cut the tops off of the bottles
3.Cut even strips from top to 'almost bottom' in ONE bottle (If you have an even number of strips you will get the pattern I have made. If you cut an odd number your colours will come out in stripes if that makes sense.)
4.Put your uncut bottle inside the cut one to act as a form
5.Weave the bag yarn in and out of the strips until you have gone as high as you want to
6.When you get to the top, cut the bottle strips into points and push them down through the first couple of rows of weaving to secure.
Hope that makes sense.