You can simply open the system_health output file in the Extended Event explorer window, or just browse to the file from the Open File menu and double-click, SSMS will figure out what to do from there. Inside that, you can use search and sort to find the deadlocks, if they're there.
"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
- Theodore Roosevelt
Author of:
SQL Server Execution Plans
SQL Server Query Performance Tuning