Language Point 3

The responsibility we have for the future begins when we recognize that we ourselves create the future — that the future is not something imposed upon us by fate or other forces beyond our control. (Para. 4)
Meaning: It is we who are responsible for the future. When we know that we ourselves create the future, that is, when we realize that it is we, not fate nor other forces beyond our control, who determine the future, our responsibility begins.
Please notice that the second "that" clause is the explanation of the first that clause.