A trolley jack is a small, hydraulic jack that can be wheeled around and underneath the vehicle. This kind of jack allows you to do such things as changing the oil. You pump the handle of the trolley jack and the fluid pressure builds within the liquid chamber of the jack. The pressure escapes through the top of the jack platform and the vehicle raises with little effort. Trolley jacks, are used along with axle stands, which support the weight of the car in case the vehicle falls. They can lift weights up to 4 tons.
They are relatively cheap, but much easier to use than the jack supplied with the car.
Make sure that you jack the car up on the correct jacking points under the sills.
Mike