If you see an icon in the middle of the screen of a disk with a blinking question mark, that means that the Mac looked all around but it couldn't find any drive that it can start booting from. If you see a smiling Mac icon, that means that it did find a disk that it can boot from. Sometimes if there is a problem, the smiling Mac disappears and goes back to the disk / question mark icon.

You have to have a System Folder on a drive for it to be bootable for your Mac and get the smile icon. We can help you with this if that's the problem.

Please try explaining in more detail exactly what is happening, or even taking pictures, video, etc. We just aren't going to understand the problem based on what you said in the original post.