In the sequence of any Surya Namaskara, or vinyasa transition, Chaturanga Dandasana is one of the most pivotal poses, and it is often the one that is the most miss aligned. This pose helps warm up the core and open up the body to prepare for the rest of the Surya Namaskara or vinyasa transition. Also if used as a static pose in a sequence helps create a fire in the belly and strengthen the core.
How to Practice
Looking at two different ways of preparing the pose.
From a Surya Namaskara/vinyasa
Starting at the top of a push up, exhale coming about half way down. It is important to keep your elbows in here and have your wrists directly under your elbows to prepare for further in the sequence. Your feet should be about hip distant apart or a little closer together. Shoulders should be melting down the rib cage away from the ears. When your upper arms are parallel with your torso you are in Chaturanga Dandasana. Inhale, flattening the toes and using the strength in both your legs and upper arms, come up into upward facing dog.
For a static practice.
I still recommend coming into the pose via the Surya Namaskara, or starting at the top of a push up, as this is a pose that is building up a fire and the flow helps keep it going. (Please see above for proper placement) when your upper arms are parallel with your torso, stay here and breath for five breaths. Then continue the exhale to either finish the Surya Namaskara, or come onto the belly for a different pose.
This is a difficult pose for anyone with wrists issues and if practiced should not be attempted in the static. If practicing in dynamic it should only be for as many rounds as feels good working up to more. If the core is strong enough, but the wrists are not, drop the forearms to the earth and compensate the distance by extending your upper arms. Use the strength in your core to keep the spine straight.
Even though it is mainly only seen in Ashtanga practices I highly recommend following any intense practice of Chaturanga Dandasana, rather it be dynamic or static, with Padangusthasana and Padahastasana. Further in the flow I also recommend working with at least one shoulder opener in standing and seated sequence. Finally, if you are practicing in the static, towards the end of the pose incorporating a light back-bends far removed from the core poses, to release the tension in the core.