Explain links between investment and dispatch

## Is your feature request related to a problem? Please describe.
It is not clear how the new investments are calculated, how is that linked with the production of each asset.

## Describe the solution you'd like
A detailed description of the procedure used to determine the investments with the detail of a timesliced-based demand.

## Describe alternatives you've considered
The documentation provides an overview of a sequence of steps as they happen in the code (workflow) but an explanation of how things are linked is needed.

## Additional context
N.A.