Before you even get a smart lock, you need to make sure that your door is cut correctly to take one (most smart locks won't work with mortise-cut doors, for instance). You should also check to be sure that the door is aligned properly with the frame so the smart lock can slide the bolt without resistance.
All right, so you've got a door that's ready for a keyless smart lock. Here in the CNET Smart Home, we're going to install the Yale Assure Bluetooth Smart Lock. Here's everything that comes in the box.
Yale includes a handy cheat sheet to make sure everything will fit in your door. You can find diagrams like this online with some quick Googling -- it's a good idea to double-check them before making a purchase.
You'll want to be sure that the turning mechanism sits right in the center of your door's opening. This is also a good time to check and make sure that the bolt will slide smoothly when you lock the door. To do so, just use a flat-head screwdriver to give it a quick turn.
There you go! You're now the proud owner of a correctly installed smart lock. To set it up, you'll want to download the lock's app and follow the pairing instructions, which will vary from lock to lock.