Shimla trip

Hey everyone! I am planning to visit Shimla for the weekend from Panchkula. I have return ticket for the toy train but not sure on how to reach Shimla. Can I get AC/Volvo bus from the Panchkula bus stand? Or do I need to go to the 43 Sec ISBT? Any help is really appreciated. Also what’s the best method to come from Kalka to Chandigarh/Panchkula? Thanks