Telephone Folding, or phone folding, means folding over the phone. You cannot see the diagrams nor the instructor, or a reference. As the name indicates, it is done over the phone, with only speech. Some people type it out. I prefer to include images of the final result.
It is quite impossible to fold a complex model by just reading the ext, but origami experts read the text and look at the diagrams for reference. I, for one, prefer to look at the diagrams only and refer to the text only if I do not understand, if the model is intermidiate or below.
The British Origami Society has a page about telephone folding.