We can push the question further back. In the abstract, we can say that some form of evolution is going to occur whenever you have imperfect replication. That

We can push the question further back. In the abstract, we can say that some form of evolution is going to occur whenever you have imperfect replication. That is the only criteria needed, and the "rules" emerge naturally such a start. You could ask, ok, why DNA based molecules and while not definitive, we have models around how their chemical precursors could become available in conditions similar to earths ancient past. You could ask why did earth have such conditions, and the answer is something like: many planets could have similar conditions, and given the size of the universe regardless of how common such conditions, one might expect them to arise like earth's somewhere. Ok, then you might ask what causes the universe have the types of stellar conditions and planetary formations and similar, to which we have cosmological models that generate these conditions from early energy states after the big bang. Ok, so then you ask what created the big bang, or the universe as whole? We don't have a great answer. But understanding how evolution itself comes to be doesn't require such a leap if we are will to accept an earlier starting point and start examining phenomenon from there.