You just need to add your “addEXP” node to the “TakeDamage” function.(Look for the ServerChangePlayerStateInfo node)
Also add a “EXPGain” variable to the Player_Parent and MonsterDB_Structure for the Monster_db then modify the “ServerSpawnMonster” node to set the EXPGain variable of the enemy.
#If HP < 1 then Addexp,EXPGain;