I am assuming you are asking for help and have already completed the standard setup of a printer:
1. Connect to power point
2. Connect to computer or router using a USB or Ethernet cable
3. Start up all computers that will be using the printer
4. Install printer drivers:
a. Manually - Insert included CD into drive, autorun, follow prompts, repeat on next machine
b. Over network - Push installer out to PCs over network, then run installers
Note that most printers should be able to work without their drivers (e.g. Canon printers are plug&play and rely on windows default drivers). If your Lexmark doesn't work straight out, and will not work with default drivers or drivers from CD, it may be faulty. This is not surprising.