Help us out please

So we are a group of 3 girls, college freshers planning to go to Shimla from chd on 28 or 29th december. We don't know how to take a bus or how to travel, we are planning one day trip , so we don't know how easy it would be travel by bus nad most importantly how will we return and if we have to spend a night there, where will we stay? We need a place that's affordable. Please guide us on how to plan this trip