no sound for Logic

I just wanted to thank the community for this post. Your information was extremely helpful. I got the 90 day test version of Logic Pro X and wanted to use it to replace my CS-6 Audition program which isn't supported (wish there was a way to run legacy programs - like a second O/S that could be activated), but, when I got it on and running, I couldn't get any sound. Of course, all my other programs worked just fine, so I knew it had to be a switch somewhere. When I clicked on audio preferences I could only get the first screen. Finding out how to get the second screen solved the problem and I now have sound. Now, I can learn about the rest of the program. By the way, is there a book on this program? Those work so much better for me than hunting for everything. Again, thanks so much for this 6 year old post. It totally helped.