The most important item to review for English Language information on this matter, is this video on YouTube:
Of all the links I can find, this video is the most serious and probably most authoritative practical guide about folding a Shi-me ( or Shi-de still trying to find out which is the correct Kanji).
Heed the warnings in the video. One should not casually or carelessly create a Shide. This is a ritual and a ritual item for the Shinto religion.
Other less formal websites include:
Shinto Ritual in words and Pictures
This article refers to the white, zigzag-folded stripes of paper as Shi-de. I do not know (yet) what the Kanji of that is.
Elsewhere, they are referred to as Shi-Me or 注連 .
Another English Language website on Shinto motifs is here: