Install the Fixture
Make sure the power is still off. Otherwise, someone might flip the switch and accidentally give you quite a shock. If the fixture involves a screw mount, screw the fixture to the mount before connecting the wires. Otherwise, you will end up with a tangled, potentially hazardous mess. Match red to red, white to white (or whatever colors your system uses). Once you twist the exposed ends of the wires together, cover with a wire nut and turn to the right. (Remember: righty tighty, lefty loosey.) Wrap with electrical tape. Be sure to ground the copper wire in the same manner as it had been before. Affix any cover plate and install the new bulbs and globes. Turn the power on at the panel and test your switch.
Even builder-grade fixtures can look like expensive fixtures. By taking a little bit of time and doing some research you can easily and inexpensively update your property's light fixtures.