We would advise you to come to the event by public transport. From stop Voorschoterlaan it is a few minutes walk to the European Championship grounds.
When you arrive in Rotterdam you have the choice to travel to the European Championships by metro, tram or bus:
By metro, take lines A, B or C to Voorschoterlaan (final destination Kralingse Zoom). Tram 7 and buses 707 and B5 also stop at Voorschoterlaan. There are signs that will bing you to European Championship site from here.
NOTE: If you come from Capelle aan den IJssel you will have to deal with activities between metro stops Capelsebrug and Kralingse Zoom. A shuttle bus will take you between these stops.
Always plan your trip before departure on https://9292.nl for the most up-to-date travel information.