Here are two sites concerning B. 'Glacier Bay'. Begonias are most difficult in the winter time for us, but you will have different experiences. Do not keep constantly wet. Give lots of humidity, filtered light, light feeding. Try to propagate by leaf or rhizome cutting for some added insurance.

I'm not sure if I agree with all this site has to say, but...
Back Yard Gardener

This is just a picture. Is this what you have?
American Begonia Society

I saw the second site/photo you most kindly posted. Here is my photo, and after seeing that photo, I 'ID'd my begonia to be one and the same, but with the bloom on it, it made it harder to be sure.

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