You can find a very detailed explanation
here.
You have an income (mass and energy), and as soon as you get something you can spend it. That's a little bit like in the real world, where you can use your credit card to buy stuff even if you don't have the money yet. If you don't spend your mass and energy fast enough it is "wasted", meaning it is lost forever.
- You need mass *and* energy to build stuff (tanks, buildings...)
- You need energy to keep stuff running (radar, shields...)
- To convert mass and energy into units, you need "build power" (factories, engineers, ...)
If you have an income of 8 mass/second, you can spend 8 mass/second. If you build a unit that consumes 16 mass/second, it will be built at half speed. If you build a unit that consumes 3 mass/second, you still have 5 mass/second left. You can use these 5 mass/second income to build an additional unit in another factory. All you need to do is keeping income and consumption in a balance.
To get mass:
- Reclaim, reclaim, reclaim. Every dead unit, every rock, every tree can give you some mass. Never stop reclaiming.
- Build T1 mass extractors (mex) wherever you can, a T1 mex pays off after 18 seconds.
- Upgrade your mexes, surround them with mass storages once they are T2. Never stop upgrading.
To get energy:
- Build power plants, lot's of them.
As a rule of thumbs:
- Always use up a little bit more mass than your income gives you, that way you don't waste anything.
- Never ever run out of energy, running out of energy is worse than running out of mass.
- Always keep enough build power ready, otherwise you may start wasting mass.
In team games I see often two issues with new players:
- They don't spend their mass, they are just wasting it.
If you have resources, use them. If you don't know how: upgrade a mex.
- They spend too much mass. That's like buying too much stuff with your credit card, the bank will get angry with you...
only start projects that you can afford. If you can't afford it now, continue expanding your economy until you can.