The search collects six hours of data matching MON001E. The timechart counts how many matches occur in each of the six hours. The eval limits those counts to be either 0 (no matches) or 1 (at least one MON001E). The stats totals the number of hours with at least one MON001E.
I interpreted your question as, "Send an alert whenever MID=MON001E occurs in six consecutive hours."