JR West Airport Express HARUKA is recommended. It takes 75 minutes and costs JPY 2,980 (non-reserved seat; reserved seat costs JPY 3,490). See also Kyoto Travel Guide.
There are three ways.
If you wish to ride on a bus or a taxi: Bus Terminal and Taxi Stand are at the north area of Kyoto Station. See Map of Kyoto Station Karasuma Chuo-guchi (烏丸中央口). See also Map around Co-op Inn Kyoto.
Kyoto City Bus is convenient (cost: JPY 220). There are 17 and 206 buses going to Yoshida Main Campus. Bus Terminal is at the north area of Kyoto Station. Taxi is also available but a little expensive (approximately JPY 1,800 per car). See Map of Kyoto Station Karasuma Chuo-guchi (烏丸中央口).
The following buses are available from Shijo Takakura (四条高倉) Bus Stop (cost: JPY 220): 3, 31 and 201. See Map around Co-op Inn Kyoto. Taxi costs a little expensive (approximately JPY 1,400 per car).
Each bus indicates its route number with color coding, e.g. No.5, No.17 and No.206. These signs will help you.
Note that 206 departs also from A3 but this bus goes to the opposite direction (via Senbon Street, 千本通).
You can find more information in Kyoto City Bus and Kyoto Subway Line (中文版) and Kyoto Travel Guide.
You can catch a taxi at Taxi Stand shown in the map.
In Kyoto city, there are many streets and each street has its own name. These street names are indicated by blue street signs as follows. These signs will help you.
Shijo (四条) K09 Subway Station (the underground walkway) has many exits. Exit 13, shown red in the above map, is the nearest to the hotel.
The following buses go from Shijo Takakura (四条高倉) Bus Stop (West), shown blue in the above map, to Yoshida Main Campus.
There are many taxis on Shijo Street. Catch these taxis, or ask the hotel staff to call a taxi.
The conference venue is Research Bldg. No.8 shown in the following map. There are Kyodai Seimon-mae (京大正門前) Bus Stop at the south-west corner of Main Campus and Hyakumanben (百万遍) Bus Stop at the north-west corner of Main Campus.