Greebles & Panels on hard surface modelling

how do you create those indented panels and greebles on a spaceship model?

like i know that you can just model something and stick it on as a small separate object on a large base mesh of a ship to get the detail.

what i don’t get is how they get the base mesh itself to look like its made from separate panels. that i just cant figure out.

sorry if i’m not making any sense.

thanks for any advice