Hi there,
When you manually add annotations to your images (photos), CoralNet considers those images to be "Confirmed".
There are a few ways to do this: the simplest way is to use CoralNet's annotation tool, but you can also upload files created with Coral Point Count (CPCe).
After you manually add annotations to at least 20 images, CoralNet can train a machine classifier which will automatically annotate the rest of your images. Those automatically-annotated images are considered "Unconfirmed". You can open unconfirmed images in the annotation tool to confirm or change the automatic annotations yourself. If the machine classifier is accurate enough, this should speed up your annotation work.
There's more to it, of course, but those are some basics to get you started in the right direction.