I shouldnt have any problem buying the train tickets at the station should I??? What would be your guys view on that????
Yes you will...but eventually you will manage.
If you are unable to buy online for some reason...(payment...site problems etc)
When you are in the big hall in the Central Station you will see ticket windows lining one wall. The farthest right two windows are for going out of Poland so even though the line will be much shorter there you have to go to the huge snaking that feeds the rest of the windows to the left for domestic tickets.
They will most likely not know any English so just write Poznan and the time you want to leave on a paper and show them. (clearly they will understand "Poznan" but the time will be an issue. The first and second class are not that different for this route so it's up to you but whichever you choose just write 1 klasa or 2 klasa on the paper too.
If you have any trouble you are best off looking for a young person near you and asking them if they speak English and can help you....the "International Help Window is usually staffed by people who only speak Polish...go figure.