Help to model a simple thread.

Help me to model a simple thread. A simple woolen thread with a knot at the end to hold like a ring.

Add Mesh:Extra Objects addon has Torus Objects - Torus Knot. Take one loop, separate Alt-P and convert to curve Alt-C.
That will give a base for the knot. Thread diameter could be adjusted on Object Data panel for curve. Model and add bevel object for the thread to give it look like i’s made from several thinner threads. Ring with scalled inwards points might do. This needs to be converted to curve before setting in knot curve properties.
Add mesh Torus and adjust inner/outer diameters and sizes on T-panel.
Position torus and curve knot, then adjust curve points to “tie” it properly around torus ring.
Convert thread curve to mesh Alt-C and add some particle hair to it. Tweak.
Hope helps.