I don't get it.
Thanks ;) What you did not get?
For example, how each of the parameters effects the planet's look, and what is the meaning of these maps that appear before the planet does..
(But honestly, it was just an ironic comment)
So, that texture, that appear before the planet, is the actual surface, that is being generated. It is wrapped around the planet after.
Size affects, how small objects on surface are.
Vegetation affects amount of green on some planets.
Temperature affects planet size. Try to set it to SUPER HOT :D
Humidity affects amount of water.
That's all ;)