The pv panel just provides the electricity to your house. Essentially, if it provides electricity, your devices use that before using the grid. If it provides excess electricity beyond what you use, it feeds back into the grid. There's nothing to it, just plug it in. Just remember that if you disconnect a circuit to work on it, you may also have to disconnect your panels because the wires may still be "hot" (they shouldn't because the PV usually stops providing electricity once it loses the grid frequency, but better safe than sorry).