The Red Eye tool is in the same palette as the Healing Brush, the Spot Healing Brush, Content Aware Move, and Patch tools. To move to this palette, press J, and click and hold on the selected icon.
Once you've selected the Red Eye tool, click on the red eye in your photo and Photoshop will fix it.
One more thought: Have you tried LevelUp for Photoshop? It's a game of missions and levels, designed to help you learn Photoshop basics; and one of the missions shows you how to fix red eye. You install LevelUp for Photoshop using Adobe Exchange. Go to Window > Extensions > Adobe Exchange, and search for LevelUp.
Product Integration Manager, Creative Cloud Learning & Training