Well, they are just 1 frame long! You imported it as an image sequence...
Ha! Yeah I'm too new. What would have been the right way to import it?
Actually, you did import it properly, as a comp. Now you need to change your comp's duration in the comp settings, and extend layer out-points after that.
But there's something else: if you're really new, you need to know that it's virtually impossible to get AE to do what you want it to do without a good knowledge of the basics. If you're trying to use it intuitively, or you're going by some high-school kid's tutorials on youtube, you're headed for a boatload of trouble and frustration.
You'll find excellent resources for the beginner here, from the folks who created the software or who are real AE Pros: people you can trust, y'know? This stuff really will help, and it's worth every minute of your time investment.