Hey Laxmi, Bir is connected to Kasol by both, state-run HRTC buses as well as private buses. Catch a morning bus from bus to reach Bhuntar around noon (110 km). From Bhuntar, you will have to take a bus headed towards Manikaran and de-board at Kasol. It'll take about an hour to cover this distance of 30km. However, with the coronavirus outbreak, I'd recommend that you avoid non-essential travel right now. Stay safe! :)