The "Tent of Meeting" and the "Tent of Service" and the Double Role of the Kohanim

Why is the fulfillment of God's command for sanctifying the Kohanim not described in its entirety within Sefer Shemot, and rather waits until the seven days of inauguration in Sefer Vayikra? Through an examination of the text we can understand the dual nature of both the Mishkan and the Kohanim.