"Herewith" is a formal word and its use here seem entirely unnecessary, The meaning appears to be "This sentence brings the explanation to a close", but I don't understand why the present perfect is used. What is the situation? Is this sentence spoken or written at the end of the explanation?
''Herewith the explanation of the eleven propositions of the pa†icca-samuppåda
formula has been brought to a close. From my explanations you will have seen that
the twelve links of the formula are distributed over three successive lives, and that
they may be applied to our past, present and future lives. The first two links, avijjå
and kamma-formations, represent the kamma causes in the past life; the next five
links, consciousness, etc., represent the kamma-results in the present life; the
following three links, craving, clinging and kamma-process, represent the kammic
causes in the present life; and the two last links, rebirth, and decay and death,
represent the kamma-results in the future life.''