After getting your luggage and passing through immigration walk forward until you are outside. Turn left and follow the sidewalk to the "limousine bus" are. There are a dozen or so numbered "bus stops" on the road to the right and some electronic ticket counters on the left. There is usually a few helpers at the ticket counters to help ensure you get to the right bus and buy the right ticket.
Looks like Kyoto is #8
Kansai International Airport | Access Information | Bus
And costs 2500 yen
kyoto sta.