Can you be more specific as to what you don't understand?
Jonathan means "
YAHWEH has given", and
YAHWEH, as written, is the name of the Hebrew God.
So your name simply means "God has given".
The paragraph you brought is an explanation about the name
YAHWEH.
The name was never spoken outloud because it was considered holy, so when it needed to be translated, they used the 4 letters Y.H.W.H that sounded (more or less) the same as the 4 Hebrew letters in the written name.