This duels plugin includes 2 kits, archer and swordsmen, archer focusing more primarily on bows and less on melee and swordsmen more on close quarters combat. To set the location where u want the duels minigame, just use the /setduellocation command, which will set where the duels will happen. To start a duel, use /duel, which will teleport you to the location you set (probably an arena or something) and will give you a menu where you can choose which kit you would like to use. You can ask a friend to do /duels and they will come to the arena as well and you both can duel.