Another way of getting to Auschwitz is to take the bus from Krakow's bus station which is located behind Krakow's main railway station at ul. Bosacka. The bus will take you directly to the Auschwitz museum, although journey times are longer than by train. Organised tours might be the preferred option for those who don't wish to use, or don't feel confident in using, public transport.
The Auschwitz museum provides a shuttle bus service (free of charge) to Birkenau that operates all year round, however it run less frequently from November until March. If there are no convenient buses available it is possible to get a taxi to Birkenau.
jewishkrakow.net/en/waryears/auschwitz