Aloha, Susanne!
It already sounds like your arrival day at Walt Disney World will be an incredible first day. I can already taste the 'Ohana Bread Pudding à la mode at '
Ohana, which is one of my absolute favorite desserts. To travel to
Disney's Polynesian Village Resort from
Epcot, the simplest way to do this is by
monorail. You'll be able to take the monorail from the front entrance at Epcot directly to the Transportation and Ticket Center then you can either enjoy a short walk to the Great Ceremonial House at Disney's Polynesian Village Resort (there will be signs directing you where to go) or transfer to a resort monorail. The first stop will be Disney's Polynesian Village Resort; and when you enter the resort, you'll see 'Ohana off toward the back windows.
If I were doing this, I'd want to leave Epcot by 3:40 pm which should allow you plenty of time to arrive in case there are any unexpected delays. Please keep in mind, too, that Epcot is a large theme park. If you are in the World Showcase when it's time to leave, you will want to allow extra time to walk to the front entrance.
Wishing you a magical trip! Please let us know if you have any further questions. -Kara