Your ignorance on the very thing you're critizing - science - is breathtaking. If you're really interested in answers to the questions you're asking, read a book
or watch a tv show in its entirety.
Mutations happen all the time and are random accidents, and obviously therefore are often detrimental to the organism... but the natural selection of which mutations will last and get handed down to future generations are anything but accidents. Those that prove advantagous for survival will often survive, those that don't, don't.
Whatever you decide to do, just know that if you're disputing evolution, you're disputing scientific fact. You can dispute the origin of life, but not evolution. Not if you want to be taken seriously.
You should watch the entire video I posted, but at least watch the 4th segment explaining the evolution of the eye. If we didn't evolve from creatures of the sea, then please explain why our eyes originally evolved to see under water..?
But by the way, I don't think evolution and intelligent design are mutually exclusive in the least. Like everyone else, I came from the church of I don't fucking know.