This מאמר is about renewal.
The counting of the Jewish people was a newness that requires:
1) שאו את ראש which means an opening of ביטול.
2) Then the actual עבודה consists of two steps:
A. במדבר סיני which is תפילה climbing from the lowest to the highest level.
B. באהל מועד which is תורה and then מצות. Bringing G-dliness down until physical action and transforming darkness to light.