Need to play single song in iTunes on Mac 10.8.5

I am making an interactive children's reading program, so am recording a lot of one-word sound files, and importing to iTunes. I've looked at preferences many times now, and don't see where to change a setting so that another song doesn't start every time I play one. I know there must be a setting for this, but I sure can't find it. Thanks in advance, I hope! 😀