Hi Mala,

Here is a picture of the required steps.
I hope it is of some help to your question.

Michel

Edit Pilou suggestion made me realize it was simpler to do it in one step, by unwrapping the whole torus.
You will get a plane of the size of the ring, and it will be easier to place ornaments on the surface.
Here is a second picture (the one with the grid) showing the process and a tip on how to move the seam of a torus.

Michel