In order to see the daily "challenges" (Called Orders in-game) you need to talk to Major Howard in the headquarters. He will have 6 daily challenges, 3 weekly and 1 special order. Up to 3 daily, 3 weekly and 1 special can be chosen at 1 time. The only orders required for this achievement are the daily ones. You can complete however many you want in a day, you do not need to do them all if you can't manage to do some of them. I do not believe that above and beyond (complete 6 in 24 hours) counts. In order to see the ones you've selected and your progress towards completing them, pause the game and scroll over to orders (works in game and in headquarters). Once an order has been completed you can turn it in for your reward by either going back to Major Howard or in the order section of the pause menu (only able to be done in headquarters).
A quick tip for the order that requires you to commend people, you're able to commend people in a lobby before a match.
Another tip for the order that has you kill 10 people with a turret in War is that you can't use tank turrets or the turrets at the beginning of the beach storming map.
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