Welcome to GoY.

I am going to assume you know nothing about them so hope you wont be insulted :o)

You should have firm fleshy tubers with a few dead stalks on the plants you have bought.
choosing a pot that allows about an inch/or2 all round the widest part of the tuber is they way I do it. I then put some good compost into the bottom of the pot sit the tuber onto it so that the junction between stalks and tuber is about 1 inch below the rim of the pot. then fill the pot with compost, shaking the pot to get the compost under all the tuber bits. water sparingly and keep the pot frost free. A shed/garage/porch will be ideal. when you see shoots breaking the surface of the compost bring them into the light.

When all danger of frost has passed then you can plant them out in the ground.

If they are going into ornamental pots then again pot them up then.

Hope this helps.

As mentioned above, when threat of frost is over, they can be planted out narrow end pointing up.

Don't make the mistake a friend of mine made - he thought that since there were several tubers connected together he could pull them apart and get several plants. It ruined every single one since the stem got destroyed and he didn't get a single plant to come up.

Thank you for your answer. I am not insulted at all.that was a really helpful reply.

That's good to know. I hope they do well for you.