I've read all the answers on How to build a cinder block wall using re-bar and concrete. My question is: How is the re-bar set in the footing to secure it and keep it standing straight up. Is the concrete put into the footing, a cinder block put down onto the wet concrete and then the re-bar is stuck into the center of the cinder block and pushed into the wet concrete? What makes it stand vertical? Just the concrete in the footing?