Well, you are not off to the best start. Never, ever consider growing plants in pots without drainage holes – particularly those native to dry climates. And, they like lots of sun.
I would leave the crown of thorns in the pot it comes in for several months at least. It will be enough for the plant to try and adapt to new growing conditions and care without stressing it by repotting. When you do decide it is time to repot it, choose a new pot only slightly larger than the pot it is in now.
Crown of thorns are sun loving plants. Getting some direct sun under a patio cover will not likely be optimal. A half a day of sun or, even better, sun most of the day is the light they prefer.
You have a friend that has been very successful with his. There will be no better source of information on how to care for your plant successfully.
Dan Gill
Consumer Horticulture Specialist
The LSU AgCenter and the LSU College of Agriculture