Watch this video from This Old House to learn how to install a stand-by generator.
1 Install electrical sub-panel with transfer switch beside the main electrical panel.
2 Redirect critical circuits from main panel to sub-panel.
3 Prepare a level stone or concrete base for the generator.
4 Set generator on base.
5 Dig trench from generator to new high-pressure gas meter.
6 Run new natural gas line and tracing wire from generator to gas meter; connect gas line to meter.
7 Pull electrical cable from generator to house.
8 Make gas and electrical connection to rear of generator.