Buying ticket at Beijing south rail station

Hi. I'm coming into South rail station at 15.07 this coming Saturday. I see the shuttle bus line 10 goes from the station to the airport. Are there ticket machines available at the rail station? Are they easy to find? The bus departs from North Square - is that marked too? I'm travelling with one large case and a backpack, but on my own so keen to understand clearly what I need to do! Thanks!