Shwann cells in neurone, help :/

I understand that the axon becomes myelinated by wrapping shwann cells around it in intervals. I would just like to know, for each node of Ranvier space on the axon is that one Swann cells wrapped infront of it, then one wrapped after it??
Also if you were labelling a diagram, how would you know what to label as a shwann cell and what to label as myelinated sheath?

Thanks x

Spelling in examinations is important. It's a 'Schwann' cell.

The answer is yes - the 'sausage roll' is a Schwann cell, which forms the myelination.