Exactly.
Here you have timetable - from PKM Katowice Sp. z o.o.
From Sunday to Friday
Departure time
01:15
03:10
06:30
10:45
11:45
12:30
13:40
14:40
15:30
17:15
18:15
19:40
20:45
23:00
00:00
08:30
In Saturday instead of 20:45 it leaves 21:45
It takes about 50 minut to get to the center.
single ticket cost 23 zł
here you have a map, where you can get off the bus
pkm.katowice.pl/docs/mapka_przystankow.pdf
where
1) Railway station
2) Sokolska street
3) Novotel hotel
4) Sosnowiec, the crossroad in Milowice