Hi,
If you are trying to achieve a transLUCENT (transparent is see-through) fabric, which has a light shining from behind - the effect in the screenshots you shared - then it can be easily done just with self-illumination. You can add a bit of sheen just for sake of it.
You can as well enable the translucency and create a light behind it, but it will give more or less the same results but with longer render times.
Hope this helps.