This will be tricky for some when it comes to the more populated games. Once you enter a Gold Rush match you will need to scramble to grab two bags and drop them in the chest. You need to repeat this three times over the course of a single match.
If you don't have enough experience with this game mode, you can find someone to setup a match with and collect the bags while they stand around.
Note: To do this on your own with other players, you will need two other people. This game mode will only spawn one bag with two players, and two bags with three.
Tips and Tricks:
You're going to want to use your strongest weapon to start with, or a weapon with a decent mid to long range unless you're playing in a crowded game. Use cover when possible and pay close attention to your map. Once you have two bags you will move slower so make sure you know where your drop chest is.
You may also want to dodge around, you can slide into cover with the and roll while aiming by pressing . Unless you play a lot of Gold Rush this may take some time to complete until you gain some experience.
See "Call it a Comeback!" for boosting information.