Power down. Pull out MPU tray. Remove old software (simms, gme, and base chips). Put in the new software except for the base chip. You put the key chip instead. Put MPU tray back on system, do clear on both options and perform the key as well (3 settings in key chip menu). Wait for the power down message. Power down, replace key chip with base chip. Power up. Then setup the key chip options like SAS, enable printer and disable hopper/acceptor (if you don't have those). Setup limits, denominations, accounting denominations, max bet. Play game.