Q.how to transplant a desert rose from one container to another
How to transplant Desert Roses from 1 pot to another slightly larger

Certified GKH Gardening Expert
You will want to put enough soil in the bottom of the new container just enough to bring the plant up to the level it was. Then fill the sides in with soil. It is best to start with moist soil, but will not hurt to water it in after.
This article will give you more information on their care: https://www.gardeningknowhow.com/ornamental/flowers/desert-rose/caring-for-desert-rose-plants.htm