Choose a lock from your local home improvement store. An external deadbolt is best for novice installers, while an internal deadbolt requires more advanced tools and specialty hardware knowledge. Be sure to choose a lock meant for the door's thickness. Most residential doors will be 1 3/8" thick, but measure yours to confirm.
Remove the deadbolt from the package. Inside, you will find a paper or plastic template that shows how to install the lock. Place this template about 6" above the doorknob, or as directed on the template.
Use a drill to establish pilot holes where shown on the template. This is where your connecting rods will be installed. Cut away a hole for the lock body using a hole saw or circle cutter.
Slide the cylinder into the hole you cut, with the keyway (keyhole) at the bottom. Slide the cylinder ring into place on the front side (outside of the apartment), and the backplate onto the cylinder from inside of the apartment. Snap the two sides of the lock together at the connecting rods.
Use the strike template or the strikeplate itself as a guide to help you cut out a hole for the bolt. Trace around the strikeplate using a pencil, then use a hammer and wood chisel to cut away the hole for the bolt. Test the operation of the lock to ensure you have done this correctly, then screw the strikeplate into place to complete the project.