This side-mission can be found by entering the Normandy’s galaxy map and having the ship travel to the following location:
Hourglass Nebula > Faryar > Daratar.
Scan the planet and locate the anomoly to begin the mission.
After you land, follow the path down the hill until you see a wide open area in front of you. You will need to protect as many of the twenty destructible crates as you can in the area. There are three YMIR Mechs cruising around and destroying them all, so in order to preserve the crates, you will need to take all of them down.
If you race down the hill at the start you will be able to attack the first two mechs without losing any crates. The YMIR that stays in the center of the area will come to attack you, whilst the second will continue off to the right. Kill the YMIR Mech in front of you, and then use your ranged weapons to aggravate the other mechs from afar. Eliminate them to complete the mission.
To the left you will find some Power Cells and over near the far right wall you can find a canister of Element Zero and a Med Kit.