Questions about example sentences with, and the definition and usage of "Kindegarten"

A: It's actually "kindergarten" but we say it like "kinder garden."
It is usually when a child first goes to regular school. It's the starting grade before they begin 1st grade and then move up the levels.
Kindergarten, then 1st grade, 2nd grade, etc.
In modern times a lot of little children will attend pre-school, as it is called. It is an early school setting where kids go before they begin official school in kindergarten.