Have you chitted them, are there visible signs of growth, can you see the eyes, if so plant with these uppermost, if none are visible then no worrys there will be plenty of dormant eyes waiting to sprout.

as Julien says if there are sprouts showing then they plant pointing upwards. If no sprouts are visible, plant them any way round you want as the potato will send the shoots up correctly.

Thankyou

One small point here,
If you already do have eyes, ?
Remove all except three eyes and you'll get better crop,
to many eyes results in a lot of top growth and small spuds because the seed potatoes put to much energy into the top growth.

I would stand with your head towards the sky, feet on the ground. Potatoes, however, with the strongest shoots pointing upwards.