Multiattack. The knight makes two melee attacks.
Longsword. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 7 (1d8 + 3) slashing damage, or 8 (1d10 + 3) slashing damage if used with two hands.
Heavy Crossbow. Ranged Weapon Attack: +3 to hit, range 100/400 ft., one target. Hit: 6 (1d10+1) piercing damage.