Casting is "different". Look up a couple videos on Wallis cast and you will see how to cast with minimal line twist. Like was mentioned, casting off the side is another method. A combination of the two is what most people use. Spending some time in your yard casting just a heavy float will help you get the hang of it. I spent about 10 hours over the course of a week wallis casting a float in my front yard before ever going to the creek, and I'm sure it saved me alot of frustration.
Most centerpins have no drag system, so the hand on the reel spool is your drag. In the winter months, guide icing can make for more tangles, so you'll get in the habit of deiceing more often or pay the price.
I have changed all of trib trout fishing to centerpinning, and really do enjoy it.