Needing a little help to setup Multisite Domain Mapping plugin

I've installed the domain mapping plugin, edited my wp-config.php file, and added the sunrise.php file to the wp-content directory. However, when I visit the multisite admin I don't see "Domains" as an option under Settings. I also don't see the site IDs under Sites>All Sites as I do in my other multisite installations. I'm sure I've missed a step, but I believe I have followed the directions properly. Thanks for the help.