I can't finish Dr. Felix's tutorial. When I enter any page, he appears, saying this:

In order to learn how to manage your pet, you should visit its Pet Profile.

In order to view a Pet Profile, visit your Stables and click on the name of a pet to view its Pet Profile.

And when I do that, this happens:

The last important thing is learning how to add a pet to your Party. If your Party is not full, then click the "Add to Party" button to add a pet to your Party.

For now, you can only have 1 Pet in your Party. You will be able to purchase additional slots from Plazas in Towns throughout Sylestia.

You can also use the Party Manager by navigating to "Party" under the "Explore" tab.

For now, click "Add to Party" to add your pet to your Party.

When I do that, the first message re-appears.

Try to add the pet to your party now. Make sure you use the button from the pet profile page and not the Party page.