Let's look at the sentence you wrote and make sure it is easy to understand and has good grammar. I will go step by step and explain the parts!
Original sentence for grammar check:
Split the scene in two parts: one is occupied by barchans of soft golden sand, the other is featuring a dry flat landscape covered in a web of cracks.
This sentence is mostly good, but we can make it clearer by saying:
Split the scene into two parts: one part has barchan dunes made of soft golden sand, and the other shows a dry, flat land covered with a web of cracks.
Now let's check the details list you gave:
"thorny shrubs, dried trees, tall cacti, solitary acacia trees with rare leaves; an oasis, a sandstorm, tumbleweed." This is a good list but we can write it as a sentence like this:
There are thorny shrubs, dried trees, tall cacti, and solitary acacia trees with only a few leaves. Nearby, you can find an oasis, a sandstorm blowing, and tumbleweeds rolling across the land.
Next, the sentence about the sun and air:
The ground is scorched by the hot sun, the air above wobbles in the heat, and sand and dust whirl up into the air.
Finally, your background:
In the distance, there are rocks with strange shapes made by the wind. Above, the sky is pale blue and without clouds.
So putting it all together:
Here's a good description you can use:
"Split the scene into two parts: one part has barchan dunes made of soft golden sand, and the other shows a dry, flat land covered with a web of cracks. Thorny shrubs, dried trees, tall cacti, and solitary acacia trees with only a few leaves grow here. Nearby, there is an oasis, a sandstorm blowing, and tumbleweeds rolling across the land. The ground is scorched by the hot sun, the air above wobbles in the heat, and sand and dust whirl up into the air. In the distance, strange-shaped rocks carved by the wind rise up. The sky above is pale blue and cloudless."