Most travelers passing through Kargil are going from Leh to Srinagar, or vice versa, and as such have booked a through ticket. Be sure to do this if at all possible. For people coming from elsewhere in Ladakh, or going to Zangskar the bus station is chaotic and it can be confusing to get a ticket. The ticket office is down a small pedestrian lane, in an unmarked large stone building, there's normally a couple of buses out front a couple minutes walk from the bus depot.