How do i start my Lexus sc300 after replacing the battery when the alarm system won't allow it?

To start your Lexus SC300 after replacing the battery and encountering issues with the alarm system, first ensure that the new battery is properly connected. Then, use your remote key fob to unlock the doors and disarm the alarm. If that doesn't work, try inserting the key into the ignition and turning it to the "on" position without starting the engine for about 10 seconds to reset the alarm. If the alarm still won't disengage, you may need to consult the owner's manual or contact a dealership for assistance.