Beekeeping and Bees

Correct. They start to build from the top and then eventually fill the whole frame.

There are several types of hives and hive frame. This is a Langstroth hive with foundation-less frames. Frames can also have a foundation for the bees to build on. The foundation can be Crimped Wire Foundation, Beeswax foundation, Plastic beeswax-covered foundation and plain Plastic Foundation.

I prefer the pictured wooden foundation-less frames because, to me, it is more natural. It can be fragile though.