Getting from Krakow to Warszawa (Warsaw) on the 8th of June opening game of European Championship

Me and a friend will do a day trip from Krakow to Warszawa to see the opening game of
the European Champion ship.
I have found this page for connections: nowy.rozklad-pkp.pl/bin/query.exe/en?
Does anyone know if it is necessary to book in advance?

Thank you!!

Yes. You'd better book in advance.

If you're going via Inter City then it's usual to reserve a seat. Kraków - Warszawa - Kraków is probably the only train journey in Poland worth paying the extra fare on the Inter City as it is actually a lot quicker than the TLK service.

Book in advance, if you are looking for a place for a pint near Warszawa Centralna you can go to this place: legendsbar.pl/index-4.html it is a 5 min walk from the station.