I think they mean
PHB:
1. When you take the Attack action
2. and attack with a light melee weapon that you're holding in one hand,
3. you can use a bonus action
4. to attack with a different light melee weapon that you're holding in the other hand.
5. You don't add your ability modifier to the damage of the bonus attack, unless that modifier is negative.
Game:
1. Doesnt* require the attack action to have been taken
2. Same
3. Same (albeit forced when using the attack action as it auto makes both attack unless you use the bonus action first, or sneak attack first. BA shouldnt be allowed first and you only get 1 attempt at a sneak, which is also wrong, you can try it until it works)
4. Same
5. Does NOT add modifier to attack and DOES add to damage