Lexus batteries are jump started using the method that works for most vehicles. A working vehicle is lined up with a car with a dead battery, and using jump leads, the working car feeds energy to the non-working car. The Lexus' battery will feed off the working car's battery, thus allowing it to charge and once again be used. You typically know that your battery is dead when the vehicle doesn't power on or electrical components, such as lights and radio don't work.
Take the keys out of your Lexus and ensure the ignition switch is not turned to the "On" position.
Park the working vehicle beside or in front of your Lexus and pop both bonnets.
Attach a positive jump lead (this is red or has a "+" sign) to the positive terminal of the Lexus battery (this is red or has a "+" sign).
Attach the other positive jump lead to the positive terminal of the working car's battery.
Attach a negative jump lead (this is black or has a "-" sign) to the negative terminal of the working car's battery (this is black or has a "-" sign).
Attach the other negative jump lead to a block of metal found somewhere under the hood of the Lexus to ground your circuit.
Start up the working car and your Lexus. Allow both cars to run for a few minutes so your Lexus' battery can charge. Remove the jump leads in reverse order.