There are many different ways to open the sheds and you will develop your own system I am sure once you start weaving and gain experience.
I can give you some tips to get started and I am sure that others in this group will also be happy to supply suggestions.
I show how I go about opening the sheds when I am weaving on a narrow warp in the first video in my WeaveZine article which you can see here........
weavezine.com/content/backstrap-basics
I have also uploaded a set of step-by-step photos to my Flikr page for those who may not, for whatever reason, be able to access the videos in the article. These kind of action sequences are best viewed on video but I have tried my best to how the technique in still shots. I hope that you find them helpful.
See them here..............www.flickr.com/photos/39560980@N05/sets/72157622748564210/
I invite other members to post about their own methods for opening the sheds when working on narrow warps.
I will open another FAQ page for wide warps.
Laverne