Not sure what brand you have purchased or what size or features it has but a typical inverter is the Xantrex. Check
here for a Xantrex manual with wiring diagrams starting on page 31.
I replaced my existing Heart inverter with a ProSine 2000 and had to install a subpanel which the original installation did not use (it used manually activated relays instead).
Make sure you use a good high current fuse and appropriate sized (LARGE) wire to the house battery bank. Those specs should be in the installation instruction information for the inverter. Try to mount the inverter as close as practical to the battery bank to minimize voltage drop.
Mount the subpanel as close to the main power panel as you can for ease of access. You will typically need to take a breaker sized to the inverter in the main panel and run a wire from that breaker to the inverter AC input. The inverter AC out goes to the subpanel. Move the items you want to be powered by the inverter to the subpanel. Remember that putting high draw items on the inverter will drain the battery bank in a hurry. Label the main power panel to note those circuits that have been moved to the subpanel.
Let us know if you have any specific questions we might answer for you.