How to attach the clips on hair extensions?

So, I bought clip on hair extensions but bought the hair and the clips seperately meaning that I have to attach them myself. Although the saleswoman explained what to do I still have NO idea how to put the things on! Can someone please explain how I attach the clips onto the hair extensions NOT how to put them in my hair?How to attach the clips on hair extensions?
You have to cut the wefts to a certain size, then sew the (Snap Clips, probably) on the weft, see the three little holes on top? you sew the side opposite of the outward opening. Or you can use super glue. Also, you space the clips inches apart on a long-ish track, not on every part of the track