How do you get to the gummi ship to enter another world in kingdom hearts

There will be two types off save points, one with a sparkly swirl, and one with a kind of vortex around it. Go to the vortex type, and save like you normally would, then go back to where it says Save, and underneatyh it should say World Map. Go to this, and you should end up in your Gummi ship ready to fly to different worlds.