Conventionally, the story of genesis says first God created the heavens and earth in 7 days.  Then he created the Garden of Eden for Adam.  He then created Eve out of Adam.  God said Adam and Eve could enjoy all the purity in the Garden except the fruit from the tree of the knowledge of good and evil.  If they ate that, they would fall.  The serpent, the most subtle of God’s creations, tricked Eve into taking the fruit of the tree of knowledge saying it would set her free to become just like God.  But if you eat contaminated fruit, you will naturally experience contaminated results.  Grasping now at inherently good and evil, we begin to become attached to what we impute to be good and averse to what we impute to be evil.  We then begin clutching at some things and fearing others.  From this emerge exploitation and violence.  From this emerges a world of suffering.  In Genesis, after being expelled from the Garden due to eating the forbidden fruit, Adam and Eve have two children, Cain and Able.  Cain becomes a farmer and Able becomes a shepherd.  Cain makes produce offerings to God, Able makes an offering of his finest lamb.  God prefers Able’s offering, Cain becomes jealous and kills Able.  As a result, Cain’s suffering multiplies seven-fold as he spawns a world of suffering and violence.  Eventually somebody comes to kill Cain, and the suffering of the world multiplies seven fold further.  Adam and Eve then have a third child named Seth, one that is good and follows God.  There is then a series of generations from this lineage until eventually we get to Noah.  At this time, God looks at the earth and sees all the wickedness that emerged from Cain’s world but then sees Noah as the one good man following God.  God then tells Noah that he regrets having created human’s outside of the Garden, and says he is going to exterminate all of creation except Noah who he will save with all those that travel with him, including the animals.  God tells Noah to build an arc so that he may be saved.  Noah does so, gathers his family and the animals, and then the rains start which flood the earth killing all of creation.  The arc floats away safely, after a long time the waters recede, the earth reappears and Noah then sets out to populate the earth.  From this perspective we are all progeny of Noah who is in turn progeny of Seth.

How can a Kadampa understand this? 

1. First, a quick note on the 7 days because people can sometimes dismiss the whole thing because they believe the earth was created over a period of billions of years worth of evolution.  Time in the God realms moves more slowly than time in the human realm.  It is perfectly possible that from the perspective of humans, it evolved over billions of human years, but from the perspective of those in the God realms it took only 7 God days.  What happens on each of the seven days follows the sequence of evolution, so there is no contradiction.  Further, when we understand emptiness, whole universes are created and destroyed in an instant.  When the ripened effect ripens, it produces entire world systems instantaneously, complete with a lengthy past.  For example, we have all had dreams where the dream world came complete with an infinite past and an infinite future, yet in reality the dream just emerged from emptiness with a mentally constructed past and future.  So there is not necessarily a contradiction here.
2. Within Genesis, out of nothingness (black near attainment of reverse order) began the emergence of subtle appearances in 7 stages (the remaining stages of increasingly gross appearance until we reach the normal waking world).  At one point, God started naming things and thereby they came into existence (objects are nothing other than mere name). 
3. According to Kadampa Buddhism, mind is the creator of all, so our root mind is God and God is our root mind.  But when we ignorantly grasp at things not being of God (meaning not created by our mind), we eat contaminated fruit and fall into a contaminated world.  We then begin grasping at some things being inherently good and other things being inherently bad (as opposed to their alternative of everything equally being completely pure creations (emanations) of God).  From this grasping at good and bad come attachment to what is considered good and anger towards what is considered bad.  From this all other delusions arise, such as the jealousy of Cain that killed Able.  From Cain’s deluded acts emerge increasingly violent and miserable worlds of suffering until eventually the beings caught up in that world cease to appear in the human world at all (Noah’s story), they have been consumed by the effects of their negative actions (metaphorically understood to be the wrath of God wiping them out) and fell into the lower realms out of karmic sight.
4. If in contrast, if we believe that everything is the creation of God, or in Kadampa terms, if you believe everything is an emanation of the definitive Spiritual Guide, the Dharmakaya, then everything functions for us differently.  Everything becomes a perfectly pure gift of God (emanated by the Spiritual Guide for our enlightenment).  Instead of everything dragging us towards the pits of hell, everything draws us up to become one with God (gather and purify all phenomena into the complete purity of the Dharmakaya).
5. Just as there is a “Tale of Two Cities” so too there is a tale of two worlds.  It is our own mind that made mistakes, and because we started following and assenting to contaminated appearances, we develop self-cherishing and other delusions which created a dream world of suffering not only for ourself but for all of the beings in our dream.  We created samsara with our mind of grasping, we take responsibility for the world of suffering we have created.  Then, like God in Genesis, we regret having created a world of suffering and we decide to uncreate it and instead start anew with only goodness and only those following God (relying upon the definitive Spiritual Guide). 
6. Genesis says everything was created by God.  Believing this enables us to see everything as pure.  This pure view then ripens us into a being who likewise creates pure worlds.  There is a branch of Christianity called “creation spirituality”, which believes pure creation is a continuous and eternal process which we celebrate in.  A Tantric practitioner does precisely this – they take delight in creating pure worlds through the power of their compassion and wisdom realizing emptiness.