Anyone familiar with History of China + Poetry?

I have an assignment due this week. We're given a poem, then need to answer 2 questions as a discussion. The last time I touched poetry was at least 15 years ago. I've read it a few times, and cannot get a grasp of it. I'd really appreciate it if someone can help me! To save space, I didn't type it out line-per-line, the capital word after a punctuation is considered as a new line of the poem.

King Wen (from the Book of Odes)

King Wen is on high; Oh! bright is he in heaven. Although Zhou was an old country, The [favouring] appointment lighted on it recently. Illustrious was the House of Zhou, And the appointment of God came at the proper season. King Wen ascends and descends, On the left and the right of God.

Full of earnest activity was King Wen, And his fame is without end. The gifts [of God] to Zhou, Extend to the descendants of King Wen; - To the descendants of King Wen, In the direct line and the collateral branches for a hundred generations. All the officers of zhou, Shall [also] be illustrious from age to age.

They shall be illustrious from age to age, Zealously and reverently pursuing their plans. Admirable are the many officers, Born in this royal kingdom. The royal kingdom is able to produce them, - The supporters of [the House of] Zhou. Numerous is the array of officers, And by them King Wen enjoys his repose.

Proufound was King Wen; Oh! continuous and bright was his feeling of reverence. Great is the appointment of Heaven! There were the descendants of [the sovereigns] of Shang; - The descendants of the sovereigns of Shang, Were in number more than hundreds of thousands; But when God gave the command, They became subject to Zhou.

They became subject to Zhou. The appointment of Heaven is not constant. The officers of Yin, admirable and aler, Assiat at the libations in [our] capital; - They assist at those libations, Always wearing the hatchets on their lower garment and their peculiar cap. O ye loyal ministers of the king, Every think of your ancestor!

Ever think of your ancestor, Cultivating your virtue, Always striving to accord with the will [of Heaven]. SO shall you be seeking for much happiness. Before Yin lost the multitudes, [Its kings] were the assessors for God. Look to Yin as a beacon; The great appointment is not easily [preserved].

The appointment is not easily [preserved], Do not cause your own extinction. Display and make bright your righteousness and name, And look at [the fate of] Yin in the light of Heaven. The doings of High Heaven, Have neither sound nor smell. Take your pattern from King Wen, And the myriad regions will repose confidence in you.

Questions:

1. Why could Zhou conquer and replace the Zhou according to the author?

2. What were the Shang (Yin) officers' attitude toward the Zhou conquerors?

From my understanding, this is all I could come up with, but not sure if it answers either of the questions: Zhou was in favor/appointed by the Heaven, so they became the ruler. The Shang officers themselves were boastful and lost the favor of Heaven. They did not look up to the Zhou conquerors and had their own way of doing things.