Key will not come out in unlocked position
I presume you figured it out by now, but if the tailpiece is installed wrong in many deadbolts, the key won't come out in one position or the other. It's called a "timing" problem and the way to fix it is to take it off the door, turn the tailpiece a half circle and put it back on the door. Usually Kwikset locks are designed so you can't put it in the wrong way, but it can happen. (If it's not the timing problem, then the deadbolt unit is defective or broken. They are designed to fail in a way that keeps them locked, so this could be a sign that someone tried to break in, or that someone used the extended bolt as a way to stop the door from closing and it hit the door frame too hard.)
The best way to install a deadbolt lock without the instructions handy is to look at the "lazy" cam and see if there is a way to install it wrong and don't install it that way. Example: If there are 2 ways for the tailpiece to fit in the deadbolt unit when the deadbolt is retracted and only one way for the tailpiece to fit in when the deadbolt is extended, then install the lock with the deadbolt extended and you can't install it wrong.