There was a nice tutorial written by QuietlyConident on the SE forums. Here is the link.
http://en.spaceengine.org/forum/11-2427-1
http://en.spaceengine.org/forum/11-2427-1
Craftsmanship looks great, as for the planet design, I'm not sure how there could be such a huge polar icecap bordering immediately on a desert. But I'm not having enough data about the planet, as it doesn't neccessarily have to be water ice, and the atmosphere density would play a role (still, there seems to be liquid water at some places, so there should be liquid water around the icecaps... unless what I think is liquid water isn't water. As I said, not enough data to go on).
If he's really basing the planet off Darwin IV, then most of its liquid water is indeed gone. However, its atmosphere is denser than ours on account of it being saturated with water vapor.
Then the planet probably is a lot colder than I suppose (common misassociation to think "hot" when you hear "desert") and average temperatures are only above freezing in the equatorial regions. That would explain the size of the icecap as well as the absence of abundant liquid water near it. It remains to be wondered how there would be so much water vapour in the air... Would be a breeze to terraform, though.