For each channel n  TRG_REQ[m]  enables (yes) or disables (no) that pair to contribute to the overall trigger request signal. 
  So for a coincidence between channels 0 and 1  you would for both channels set TRG_REQ[0] and TRG_REQ[1] to "yes" and Operation Mask to AND

Operation Mask: Sets the logic operation among the enabled trigger request signals.  Options are OR; AND; majority

Majority Threshold: Sets the majority level. For a level m the majority fires when at least m+1 trigger requests are high

LVDS I/O Global Trigger: when enabled the global trigger from LVDS I/O participates in the trigger validation generation (in logic OR)

LVDS I/O Individual Trigger: when enabled the individual trigger from LVDS I/O participates in the trigger validation generation (in logic OR)

External Trigger: when enabled the external trigger from TRG-IN front panel connector participates in the trigger validation generation (in logic OR)

Software Trigger: when enabled the software trigger participates in the trigger validation generation (in logic OR)