You can download the full manual from the Garmin website.
Go to the FPL button, select page 1 for active FPL or page 2 for stored FPL. Select MENU and select Enter new FPL.
Start entering the waypoints. When complete, press MENU to activate or store the FPL.
When the FPL is active (FPL 0) and the OBS selector is set to GPS not NAV then the nav information will be available on the HSI or CDI. If this HSI or CDI is coupled to the NAV mode of the autopilot then the A/P will track the GPS signal.
If you don't have a Sandel HSI or similar with autoslew function, at each waypoint you will have to set the HSI arrow to the new desired track for the next sector.
I find the Garmin 430 very intuitive ad rarely need the manual after the first couple hours.