The requirements are:
You have well leveled Zeus
You have well leveled Energy Shields
You are at HQ4
You have at least 900 resource production per minute
It is also recommended:
Well leveled Assault Vehicle Factory production time reduction
Well leveled Support unit, either Typhoon (recommended for beginners) or Vertex (requires very good timing and control)
Build your buildings in the following order:
2 or 3 (Legend League recommended) lvl 3 Assault Vehicle Factories
1 lvl 3 Special Vehicle Factory
If you want to go for Typhoon: 1 lvl 1 Special Vehicle Factory (optional)
If you want to go for Vertex: 1 lvl 2 Avia Factory and 1 Airfield
Make sure your enemy doesn't go to heavily for avia before committing to this strategy and choose something else if they do.
Your main focus is to start producing Zeus as they are the unit you need the highest number of, so it is recommended to prepare the Assault Vehicle Factories you need first and start producing Zeus without pause. While you produce them you can start to get your lvl 3 Special Vehicle Factory. You only need 2 or 3 Energy Shields which means that it is not necessary to start their production immediately and it can be delayed a bit.
After you have your Energy Shields produced you should start working on getting your auxiliary unit. In case you decided to go for Typhoons your aim is to create 6 of them as they are easily able to deal with 4 Hawks (which is what is considered not going for avia too heavily) if combined with an Energy Shields. If on the other Hand you decided to go for Vertex, than 4 should be enough. Going for Vertex also means that you can build 1 single Cyclone which might come in handy later on.
You want to attack when you reach full CP for your current HQ level. So expect to be forced to control quite a big army. It is important to note that Energy Shields have a higher Speed than Zeus which means you have to either use the strategic button (3 vertical arrows) to force them to move at the same speed, or manually pay attention so your Energy Shield always remains closely behind your Zeus.
If you decided to go for Typhoon, than they should be placed shortly behind your energy shields in the formation. This allows them to also benefit from the Energy Shields protection, while also being close enough to actually attack incoming Avia. Which is one of the main weaknesses of this choice, as a skilled player can very easily minimize the effect of your Typhoons by using U-Turn Hawk / Vertex tactics.
This is where the advantage of using Vertex as auxiliary unit comes into play, as 4 of them are just enough to kill 1 or more Hawks (they tend to fly very close together, therefore allowing you to hit other Hawks through splash damage too) in one single shot. You have to be very careful though to not fly into the enemy's Anti Air units which is the main difficulty with using this auxiliary units as you will still have to simultaneously control your Zeus and Energy Shields.
You basically continue to approach your enemies base this way and there are only 3 things which could stop you now:
Mines: Some Resistance players tend to mine huge parts of the map, therefore forcing you to clean up a path by force firing at the mines.
Chameleon: You can deal with it by Force Firing into the fog, whether you try to first take care of the Chameleon or Jaguars is personal preference, but it is recommended to try to take out the Chameleon first.
Hills: Hills give a huge advantage to resistance as Jaguars and Mammoths both have only 1 weapon which can be Force Fired. While Force firing from a hill, these units are not revealed, which makes it very similar to facing against chameleon. A good way to overcome this is to have a Cyclone with you, which you place, so it barely shows the first few cells on top of the hill, in stand-ground mode (arrow with a red cross over it tactical button bar). This allows your ground units to see the enemies as if they were on a normal plain.
When you dealt with all the issues mentioned above, there will basically be nothing left to stop you from winning. Not even mass grenadiers need to be feared as Zeus with Energy Shields literally crush them.
Note:
Do NOT underestimate the time it takes to fight your way to your enemy
Practice this tactic first, especially the part where you produce your units
In 2v2 games it is viable to completely forego any auxiliary unit if your partner goes heavily for Vertex, making this tactic even more deadly
If you go for this tactic and see your partner getting attacked, go for offense instead and fortify your base with towers, as Zeus are far to slow to be able to reach your partner in time