First buy some sheet netting......it's basically a long net without the running lines...
I do it outside ..got a nail on my outhouse...about 6 foot off the ground....then get your sheet netting out it's bag and hook each end mesh one after the other on to the nail.....the end meshes are the ones that are freyed where they have been cut...there will be 15 or them.....I have 2 marks on the wall...4 foot and 4 foot 6....cut the netting at the desired length ....making sure to leave plenty of length on the cut mesh.....this is so it's easy to tie the length of nylon your going to briad the