tie all the strings together in one big knot at one end, you need about 24 lengths of baler twine,,,,, then knot pairs of twine together, then, depending upon what hole size you need, you do another knot with opposite pairs of twine..... a bit like when you do that lacey trellis plait in a horses mane.... keep going till the end of the strings and put a lenghth of plaitted twine through the last of the diamond shapes that have been created.....
Big bottle of wine if you understand those instructions!!!
I loved making one! (unfortunately it turned out a funny shape and was pretty much useless but I didn't care) - to add to the instructions on the link, its quicker, easier and more accurate if you get a stick or piece of wood to measure out the lengths of the hole each time.
AAHHH! that reminds me of whn I was a kid, we used to sit in the feed room making them! Don't think we ever used them but kept us busy and dry for a while!