The dyson sphere works as a resource sink and is capable of producing 1TW of power.
There are 4 Build stages to "build the dyson sphere".
Once all 4 build stages are completed it will then produce power you will then need to provide the items before the cargo departure or the power output will be decreased.
When you first unlock the dyson sphere you will only have Hangar1 unlocked and will only produce max of 250GW, Unlocking all 4 hangars will give you 1TW of power.
Hangars can be unlocked from the HUB and each hangar will increase the Cargo Departure time allowing for more time to fill the dyson sphere.