Use VLC Media Player or MPC-HC . They are free and come with all the "codecs" needed to play HEVC and MKV files without extra setup.
Because the file uses the codec and is an .mkv (Matroska) container, some standard players (like older versions of Windows Media Player) might struggle. Use VLC Media Player or MPC-HC
MKV files often have multiple audio tracks. If you don't hear anything, right-click in your player, go to Audio > Audio Track , and try a different option. right-click in your player