Just think, for evolution to be true, every creature on earth—the simplest of which is sophisticated beyond our wildest imaginations—has to be the product of billions upon billions of chance mutations. That’s quite a run of dumb luck!
Trial and error, with feedback, work wonders.
I saw, within the last couple of days, probably on one of these threads, an example that may help you understand the "billions and billions" bit.
With, say, a dozen dice what are the odds of rolling all sixes? Pretty high, right? That is what you are doing when you suggest the odds against evolution of a particular trait is "billions and billions" against.
But evolution works with trial and error and feedback. A closer analogy would be when you roll that dozen dice you do a second roll with only those that did not produce a six. Then a third roll and so on until they are all sixes. When you do it that way getting all sixes is pretty easy.
That is a much better analogy for how evolution works, with trial and error and feedback.