What I have usually found to hold true in seed starting (maybe not always, but usually...)
a tomato is a tomato is a tomato- what works for one type holds true for other tomatoes, too
a petunia is a petunia is a petunia
a begonia is a begonia is a begonia, etc.
Other begonias want light and good heat to germinate, so my guess would be that these do too. Assuming it is tiny like most begonia seeds, that would indicate surface sowing to me. And plenty of humidity (dome) and bottom heat.
Karen
