Basic order of what to do:
1. Destroy initial Cube and Spheres in front of the players.
2. Go to left (or right, tho left is most common side people go to) side, there will be a transformer, surrounded by 4 generators, and a Cube and Sphere (Advanced) or just a Sphere (Normal), destroy the Cube/Sphere first.
3. Bring all 4 generators down to 10%, and then destroy all 4 simultaneously. The reason for this is that once any generator is destroyed, repair spheres/probes will start coming to repair them and the transformer.
- 3a. Assuming you managed to destroy the generators at the same time, you should have enough time to destroy the transformer before spheres can repair it. So everyone must focus fire on transformer to destroy it quickly. Someone can try to crowd control the spheres to prevent them from getting to the transformer as well, as this can buy more time to destroy the transformer. Destroy any remaining spheres.
- 3b. If you failed to destroy the transformer quickly and the spheres/probes have started repairing it, you must destroy any spheres/probes first, and then finish off the transformer after they're destroyed (while probes are repairing the transformer it is for all intents and purposes indestructible). Note, if any of the spheres/probes repaired the transformer, you have failed one of the optional objectives, and will receive less marks at the conclusion.
4. Repeat Step 3 for other side. Note that after the second transformer is destroyed, the Tactical Cube endboss will spawn, it's best to avoid aggroing it, so you can complete step 3 for second side.
5. Destroy the Gate. You can do so safely from 9km+ out from it, as beyond 9km it cannot attack you. If the Tactical Cube has been aggroed, just stay on opposite side of the gate as the Cube, as it is slow and can't navigate around the gate easily.
6. Destroy the Tactical Cube.
7. Mission complete.