Vyaan mudra is one of the variations of Vata-Karak mudra. It helps to manage Vyaan Vayu.
How to do Vyaan mudra:

Join the tips of index thing and thumb finger and now place the tips of the middle finger above it just like in the picture.
What is Vyana Vayu and How Vyaan mudra helps
Vyana Vayu, one of the five subdivisions of life force, Prana, strengthens the body’s distribution and communication systems. Integra and coordinate the other four Prana Vayus, keeping them balanced and fed. Vyana is a force of penetration and expansion that controls the movement of prana through the nadis (energy channels). the movement of energy through the circulatory system and the nervous system; and the free flow of thoughts and feelings in the mind.
Vyana also controls the muscles, coordinates the balance and regulates the movements of the nucleus towards the periphery. Because Vyana pervades the entire body, it is particularly active in the extremities and helps them develop the forces of locomotion and manipulation, two of the five Karmendriyas (or active senses). The expansive quality of Vyana with the help of Apana Vayu (downward force) is fixed and anchored by the legs and is particularly noticeable in the arms, as evidenced by its ability to provide comfort and healing.
Vyana mudra practice helps to balance and strengthen Vyaana Vayu.
Benefits Of Vyaan mudra:
This mudra is used for ailments of the heart and the blood circulatory system,
Duration of Vyaan mudra practice:
30 t0 45 minutes of regular practice is enough to get good results.