If you already have PES 2016 in your library, the UEFA EURO 2016 content should appear as an automatic update or a free download in your DLC section.
If you’re looking to dive back into on your PC, you’re likely looking for the specific Data Pack that Konami released to celebrate the tournament. Originally, this was launched as a free DLC for anyone who already owned Pro Evolution Soccer 2016. How to Get the Game Today pes-uefa-euro-2016-france-pc-game-free-download
Konami also released a standalone physical version for those who didn't own the base game, which included the full PES 2016 experience plus the Euro 2016 content. If you already have PES 2016 in your