What you have there are Crocus corms. They are not seeds and should not be thought of as such since their needs and growth are different.

When you say 'winter bulbs' what exactly do you mean? Are you wanting them to flower indoors? Or outdoors?

If you want them outdoors just plant them in the open ground at 3 x the depth of the bulb. They will flower in early Spring with no further intervention from you. If you want them in a pot outdoors plant them in container compost. In my climate I would leave them outdoors but in yours it would probably be best to put the containers in a frost free shed or garage so they don't freeze solid. Don't cover the pots in plastic.

If you want them to flower indoors Google 'forcing crocuses'. They need to be planted in their pots then kept in a cold dark place, such as a shed, until you see shoots. Then they can be brought into the light and more warmth. But the cooler you can keep them in the house the longer the flowers will last.

There is a bulbs forum here on GW where you can get specific bulb advice and which is busier than this forum.

Thanks a lot for clarifying! I wasn't sure of the English word but seed didn't sound right. I will do as you advise and keep them out of the frost. I'll also look for the bulbs forum, thanks again!

They only need to be kept from freezing if they are in pots. In the ground they would be absolutely fine. The Bulb Forum is here. Good luck.