The how, when and why of Creation provide a framework which enables us to develop our picture of God and a foundation on which to build our knowledge of the truth.
This knowledge mandates that I accept a literal Biblical, recent creation of life on earth, and a literal Adam & Eve. Nothing else makes sense.
It would be impossible to fit all the pieces together without this foundation in Genesis. This was and is essential to my understanding of who God is and hence essential to my relationship with Him. 
I could, perhaps, be in a saving relationship with Jesus without being convicted on this issue, however the true picture of God’s character would be severely obscured by my acceptance of any variant of atoms-to-Adam, mud-to-me, fish to philosopher evolution.
I want the whole truth, not just pieces here and there.

William Provine, an evolutionist, put it more strongly:
"belief in modern evolution makes atheists of people" and "one can have a religious view that is compatible with evolution only if the religious view is indistinguishable from atheism."

One thing I can say with certainty is that if I didn't accept, as a minimum, a literal 6-day creation of all life on earth around 6,000 years ago, then I would struggle to be a convicted and committed member of God's remnant Seventh-day Adventist church. I would be in a continual state of spiritual tension and discomfort as a professed Adventist and, indeed, as a thinking Christian.
As it is, I am at perfect peace over this issue, since God revealed it to me as irrefutable truth.  

How did God create?
The Bible says God (Jesus) "spoke" the universe into existence.
He used His "power", His "wisdom", His "understanding".
This is obviously beyond human understanding.
I look forward to understanding a lot more in the millennia to come.

As far as life on earth (at least) is concerned, during the literal Creation week, around 6,000 years ago.
The Bible is quite clear on this.
Most Hebrew scholars agree that the writer of Genesis clearly intended the six days of creation to mean six literal, 24-hour days. 
The remainder of the Bible overwhelmingly supports this exegesis (interpretation).
If we trust that God doesn’t want to mislead us, then we did not "evolve" from molecules over billions of years.
God created a literal Adam and Eve, and all of His creation was perfect.
God didn’t compromise by using "theistic evolution", "progressive creation" or a "gap" or "staircase" mechanism over millions of years.
I cannot compromise either.
If I accepted any flavour of molecules-to-man evolution, then I must accept a less-than-perfect, even dishonest god.
If I dismiss Biblical creation, I must logically dismiss the Bible.
Biblical creation is the foundation on which sits the Gospel (the good news) of Jesus.
Biblical creation is the only piece that fits perfectly the picture of a perfect God.
That’s where I came from.

For me, the WHY of Creation was one of the bigger pieces of the puzzle.
Why did God create us?
The answer is simple*, yet profoundly beautiful and infinitely powerful.
God’s character, His very essence, is outward-focused, other-centered love.
(This can be difficult to relate to, but it’s a fact. To me, it’s mind-boggling and life-changing.)
The triune God is therefore a relational Being.
He/They created us in order to share His/Their love with us, in a personal and eternal relationship.
A totally selfless motive for our creation.
"Wow" I thought, when the penny dropped.
That’s why I’m here!

Fundamental Belief No. 6 - Creation

The Bible tells of other created worlds. We believe the universe is old and that God has been creating for a long time! The creation week in Genesis refers only to earth, life on earth and our immediate neighborhood.

Here is an outline of proposed theories for Genesis 1:1-2.

Excerpt from the book "Seventh-day Adventists Believe"-
"What Are the "Heavens" that God created in the beginning?
Some people are puzzled, and understandably so, by the verses that say that God "created the heavens and the earth" (Gen 1:1 Gen 2:1 Ex 20:11) and that He made the sun, moon, and stars on the fourth day of Creation week 6,000 years ago (Gen 1:14-19). Were all heavenly bodies brought into existence at that time?
Creation week did not involve the heaven that God has dwelt in from eternity. The "heavens" of Genesis 1 and 2 probably refer to our sun and its system of planets.
Indeed, the earth, instead of being Christ's first creation, was most likely His last one.
The Bible pictures the sons of God, probably the Adams of all the unfallen worlds, meeting with God in some distant corner of the universe (Job 1:6-12)"

*a complimentary and more nuanced view is in this article: Our Creator God  (PDF here)