When you pick up a standard in battle, survive until the end of battle and then select it (so that it's in your hands) and wait a few seconds and it'll be added to your inventory. You can do this with muskets and swords too.

If you wait too long, you'll be kicked out to the casualties screen and lose the standard forever, and if you die before the battle is over, then you don't get to keep any items you scavanged.

引用自 Bluehawk：

When you pick up a standard in battle, survive until the end of battle and then select it (so that it's in your hands) and wait a few seconds and it'll be added to your inventory. You can do this with muskets and swords too.

If you wait too long, you'll be kicked out to the casualties screen and lose the standard forever, and if you die before the battle is over, then you don't get to keep any items you scavanged.

Alright, thanks.