Well, not knowing what you do or don't know already... it's hard to say where to start.
You expressed curiosity about 'chance' in evolution... perhaps we can start there?
As Sandy pointed out, what looks totally like chance on the surface is actually a bit more complicated than that.
The genes of parents combine in their children under some fairly predictable "rules" (I put rules in quotes because there isn't a hard law regarding this, just probability). Each time this happens little changes sneak into the next generation, mutations and new combinations of features. This is why kids are never exact copies of their parents.
And aren't we all happy about that!
This fact is the basic foundation of Evolution. "Decent with modification" or in more technical terms "change in allele frequencies over time" (alleles are different varieties of genetic traits in the DNA, such as brown eye or blue eyes.)
While the exact nature of these changes can't be predicted exactly, we do know that certain things don't happen. Dogs will never give birth to cats for example. This is the sort of change that is simply too extreme to ever expect. It would require too much change.
In fact if it ever did, it would be evidence against evolution!
I won't go into all the details about how DNA gets copied and how genes from parents come together to make a child... if you have anything you want me to explain further just let me know and I'll try to help you with it.
I know evolution is a difficult subject to learn and understand... I'm still learning myself and I've been at this a while.
But that is part of why I enjoy learning about it so much. It keeps me on my toes and it gives me more and more respect for creator to try to understand just how much goes into making things the way they are today. And to know that it isn't over yet! How amazing is it that the process of creation still continues for us to witness!
I hope that what I've said helps a little!
wa:do
ps. If I ever use a term you don't understand, let me know! I'm used to the rather odd science terms that we biologists toss around when we talk... sometimes I forget what a 'normal' word and a 'technical' word are! I try to never use such words without trying to explain them, but I understand if my explanations aren't quite good enough.