My car is 2017 GSF which is quite different from yours. 😊 The below is the idle learning procedure for my car directly from Lexus factory service manual. Hope it helps.
Idle Learning
Turn the engine switch off and wait for at least 30 seconds.
Start the engine and warm it up until the engine coolant temperature is 80°C (176°F) or higher.
HINT:
Learning starts when the engine coolant temperature is 80°C (176°F) or higher.
After the engine is warmed up, allow it to idle for 5 minutes with the air conditioning and all accessories off.
Confirm that the idle speed is within the specified range.
Standard:
Engine Idle Speed
700 to 800 rpm
HINT:
Be sure to perform this step with all accessories off.
Make sure that the shift lever is in N.
Make sure that the electric cooling fan is off.
