I can't remember now, but back when I did need to do it Google gave plenty of tutorials and it was really straightforward.
You need to enable the timeline first (windows>Timeline) and then create different frames by enabling the vision of layers (eye icon). After all this it depends on your Photoshop version how to export/save the gif file. As mentioned google will have indepth tutorials on it.
Good question... Actually, I love ps for Making GIF, specially. First you can learn by YT, Then you'll find the way of making GIF. Check this basic tutorial . http://blog.hubspot.com/marketing/how-to-create-animated-gif-quick-tip-ht
I am an expert at Adobe Photoshop cs4. Fuck cs6! I'm old school. I still use GIMP to this day. If you need any adive just message me